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PD_AMORPHOUS
CIF
This section contains information about peaks in an amorphous phase
extracted from the measured or, if present, the processed diffractogram.
Each peak in this table will have a unique label
(see _pd_amorphous.peak_id).
See PD_PEAK for details on the specific peak parameters that may be recorded. Each amorphous peak may or may not be associated with an indexed reflection, and as such, an "amorphous" phase could represent a material with a unknown crystal structure. Amorphous peaks do not correspond to background, and should not be used as such.
Note that peak positions are customarily determined from the processed diffractogram, and thus corrections for position and intensity will have been previously applied.
_pd_amorphous.peak_id
CIF
An arbitrary code is assigned to each peak in an amorphous phase.
Used to link with _pd_peak.id. Each peak will have a unique code. In cases
where two peaks are severely overlapped, it may be desirable to list them as
a single peak.
A peak ID must be included for every amorphous peak.
_pd_amorphous.phase_id
CIF
The phase (see _pd_phase.id) to which the amorphous peak relates.
PD_BACKGROUND
CIF
This category defines various background functions that could be used when calculating diffractograms.
The data items list here allow for the recording of the various coefficients
used, rather than a complete enumeration of the value of the background
calculated at every data point; although doing so is still possible - see
_pd_proc.intensity_bkg_calc.
The computed background values should include all normalization corrections,
and thus are specified on the same scale as the observed intensities
(_pd_meas.counts_* or _pd_meas.intensity_*, and _pd_calc.intensity_total).
If more than one type of background is specified for a particular diffractogram, then it is assumed they are linearly additive.
Examples:
_pd_diffractogram.id A_DIFFRACTION_PATTERN loop_ _pd_background.id _pd_background.air_or_thermal_diffuse_order _pd_background.air_or_thermal_diffuse_coef_1 _pd_background.air_or_thermal_diffuse_coef_2 1 0 1.5 0 2 1 0.0747 0.954 3 2 0.00132 0.912
_pd_diffractogram.id A_DIFFRACTION_PATTERN loop_ _pd_background.id _pd_background.air_or_thermal_diffuse_coefs_1 _pd_background.air_or_thermal_diffuse_coefs_2 1 [1.5 0.0747 0.00132] [0 0.954 0.912]
_pd_diffractogram.id A_DIFFRACTION_PATTERN loop_ _pd_background.id _pd_background.Chebyshev_order _pd_background.Chebyshev_coef _pd_background.Chebyshev_coef_su _pd_background.X_coordinate 1 0 4.219 1.30 time-of-flight 2 1 25.114 1.62 time-of-flight 3 2 -10.012 1.02 time-of-flight 4 3 6.720 0.66 time-of-flight
_pd_diffractogram.id A_DIFFRACTION_PATTERN loop_ _pd_background.id _pd_background.Chebyshev_coefs _pd_background.Chebyshev_coefs_su 1 [4.219 25.114 -10.012 6.720] [1.30 1.62 1.02 0.66]
_pd_diffractogram.id A_DIFFRACTION_PATTERN loop_ _pd_background.id _pd_background.line_segment_X _pd_background.line_segment_intensity _pd_background.X_coordinate 1 5.0 150.7 2theta_corrected 2 10.0 74.3 2theta_corrected 3 20.0 36.5 2theta_corrected 4 40.0 33.2 2theta_corrected 5 80.0 24.5 2theta_corrected 6 147.0 35.6 2theta_corrected
_pd_diffractogram.id A_DIFFRACTION_PATTERN loop_ _pd_background.id _pd_background.Chebyshev_coefs _pd_background.polynomial_coefs _pd_background.polynomial_powers _pd_background.X_coordinate 1 [4.219 25.114 -10.012 6.720] [1049.69 5016.63] [-1 -2] 2theta
_pd_background.air_or_thermal_diffuse_coef_1
CIF
The value of the first coefficient used in an equation representing the
background due to thermal diffuse scatering and/or air scattering, in a
calculated diffractogram. This equation can account for background
contributions at both high and low q. The first coefficient accounts for
background contributions that increase with q. Must be given with a
_pd_background.air_or_thermal_diffuse_order value.
The background equation is of the form:
bkg = Sum( C1~j~ * (q~2*j~/j!) + C2~j~ * (j!/q~2*j~), j=0:N)
where C1 and C2 represent _pd_background.air_or_thermal_diffuse_coef_1 and
coef_2, respectively, j is the order of the equation as given in
_pd_background.air_or_thermal_diffuse_order, and q is the magnitude of the
diffraction vector, defined as
q = 4 * Pi * sin(theta) / lambda
where theta is the diffraction angle and lambda is the wavelength of the incident radiation in angstroms.
_pd_background.air_or_thermal_diffuse_coef_1_su
CIF
Standard uncertainty of pd_background.air_or_thermal_diffuse_coef_1.
_pd_background.air_or_thermal_diffuse_coef_2
CIF
The value of the first coefficient used in an equation representing the
background due to thermal diffuse scatering and/or air scattering, in a
calculated diffractogram. This equation can account for background
contributions at both high and low q. The second coefficient accounts for
background contributions that decrease with q. Must be given with a
_pd_background.air_or_thermal_diffuse_order value.
The background equation is of the form:
bkg = Sum( C1~j~ * (q~2*j~/j!) + C2~j~ * (j!/q~2*j~), j=0:N)
where C1 and C2 represent _pd_background.air_or_thermal_diffuse_coef_1 and
coef_2, respectively, j is the order of the equation as given in
_pd_background.air_or_thermal_diffuse_order, and q is the magnitude of the
diffraction vector, defined as
q = 4 * Pi * sin(theta) / lambda
where theta is the diffraction angle and lambda is the wavelength of the incident radiation in angstroms.
_pd_background.air_or_thermal_diffuse_coef_2_su
CIF
Standard uncertainty of pd_background.air_or_thermal_diffuse_coef_2.
_pd_background.air_or_thermal_diffuse_coefs_1
CIF
List of the first coefficients used in an equation representing the background due to thermal diffuse scatering and/or air scattering, in a calculated diffractogram.
See _pd_background.air_or_thermal_diffuse_coef_1.
The position of the coefficient in the list is significant, denoting the order to which it corresponds. The first is the zeroth order, the second is the first, and so on.
_pd_background.air_or_thermal_diffuse_coefs_1_su
CIF
Standard uncertainty of pd_background.air_or_thermal_diffuse_coefs_1.
_pd_background.air_or_thermal_diffuse_coefs_2
CIF
List of the second coefficients used in an equation representing the background due to thermal diffuse scatering and/or air scattering, in a calculated diffractogram.
See _pd_background.air_or_thermal_diffuse_coef_2.
The position of the coefficient in the list is significant, denoting the order to which it corresponds. The first is the zeroth order, the second is the first, and so on.
_pd_background.air_or_thermal_diffuse_coefs_2_su
CIF
Standard uncertainty of pd_background.air_or_thermal_diffuse_coefs_2.
_pd_background.air_or_thermal_diffuse_order
CIF
The value of an order used in an equation representing the background due to thermal diffuse scatering and/or air scattering, in a calculated diffractogram. Must be given with a _pd_background.air_or_thermal_diffuse_coef value.
The background equation is of the form:
bkg = Sum( C1~j~ * (q~2*j~/j!) + C2~j~ * (j!/q~2*j~), j=0:N)
where C1 and C2 represent _pd_background.air_or_thermal_diffuse_coef_1 and
coef_2, respectively, j is the order of the equation as given in
_pd_background.air_or_thermal_diffuse_order, and q is the magnitude of the
diffraction vector, defined as
q = 4 * Pi * sin(theta) / lambda
where theta is the diffraction angle and lambda is the wavelength of the incident radiation in angstroms.
_pd_background.Chebyshev_coef
CIF
The value of a coefficient used in a Chebyshev polynomial equation
representing the background in a calculated diffractogram. Must be given
with a _pd_background.Chebyshev_order value.
The Chebyshev polynomial is of the first kind, and can be represented by the recurrence relation
T~0~(x) = 1 T~1~(x) = x T~n+1~(x) = 2 * x * T~n~(x) - T~n-1~(x).
where n represents the order of the polynomial, and x is the X-coordinate in which the diffractogram was calculated, normalised to the range -1:1.
The background equation using Chebyshev polynomials is of the form:
bkg = Sum( coeff * T~n~(x))
_pd_background.Chebyshev_coef_su
CIF
Standard uncertainty of pd_background.Chebyshev_coef.
_pd_background.Chebyshev_coefs
CIF
List of coefficients used in a Chebyshev equation representing the background in a calculated diffractogram.
See _pd_background.Chebyshev_coef.
The position of the coefficient in the list is significant, denoting the order to which it corresponds. The first is the zeroth order, the second is the first, and so on.
_pd_background.Chebyshev_coefs_su
CIF
Standard uncertainty of pd_background.Chebyshev_coefs.
_pd_background.Chebyshev_order
CIF
The value of an order used in a Chebyshev polynomial equation
representing the background in a calculated diffractogram. Must be given
with a _pd_background.Chebyshev_coef value.
The Chebyshev polynomial is of the first kind, and can be represented by the recurrence relation
T~0~(x) = 1 T~1~(x) = x T~n+1~(x) = 2 * x * T~n~(x) - T~n-1~(x).
where n represents the order of the polynomial, and x is the X-coordinate in which the diffractogram was calculated, normalised to the range -1:1.
The background equation using Chebyshev polynomials is of the form:
bkg = Sum( coeff * T~n~(x))
_pd_background.cosine_Fourier_series_coef
CIF
The value of a coefficient used in a cosine Fourier series equation
representing the background in a calculated diffractogram. Must be given
with a _pd_background.cosine_Fourier_series_order value.
The background equation using a cosine Fourier series is of the form:
bkg = C~0~ + Sum( C~j~ * cos(x * j), j=1:N)
where x is the 2 value for that particular step, or some other
X-coordinate normalised to the range 0:180 degrees, j is the order
of the coefficient, and N represent the upper limit on the number of
coefficients used.
_pd_background.cosine_Fourier_series_coef_su
CIF
Standard uncertainty of pd_background.cosine_Fourier_series.
_pd_background.cosine_Fourier_series_coefs
CIF
The value of a coefficient used in a cosine Fourier series equation representing the background in a calculated diffractogram.
See _pd_background.cosine_Fourier_series_coef.
The position of the coefficient in the list is significant, denoting the order to which it corresponds. The first is the zeroth order, the second is the first, and so on.
_pd_background.cosine_Fourier_series_coefs_su
CIF
Standard uncertainty of pd_background.cosine_Fourier_series_coefs.
_pd_background.cosine_Fourier_series_order
CIF
The value of an order used in a cosine Fourier series equation representing the background in a calculated diffractogram. Must be given with a _pd_background.cosine_Fourier_series_coeff value.
The background equation using a cosine Fourier series is of the form:
bkg = C~0~ + Sum( C~j~ * cos(x * j), j=1:N)
where x is the 2 value for that particular step, or some other
X-coordinate normalised to the range 0:180 degrees, j is the order
of the coefficient, and N represent the upper limit on the number of
coefficients used.
_pd_background.Debye_diffuse_amp
CIF
The value of the amplitude in a Debye diffuse scattering equation representing the background in a calculated diffractogram.
The background equation is of the form
bkg = amplitude * sinc(distance * q) * exp(-displacement * q^2^)
where sinc(X) is defined as
sinc(X) = sin(X) / X
and where q is the magnitude of the diffraction vector, defined as
q = 4 * Pi * sin(theta) / lambda
where theta is the diffraction angle and lambda is the wavelength of the incident radiation in angstroms.
_pd_background.Debye_diffuse_amp_su
CIF
Standard uncertainty of _pd_background.Debye_diffuse_amp.
_pd_background.Debye_diffuse_displace
CIF
The value of the displacement in a Debye diffuse scattering equation representing the background in a calculated diffractogram.
The background equation is of the form
bkg = amplitude * sinc(distance * q) * exp(-displacement * q^2^)
where sinc(X) is defined as
sinc(X) = sin(X) / X
and where q is the magnitude of the diffraction vector, defined as
q = 4 * Pi * sin(theta) / lambda
where theta is the diffraction angle and lambda is the wavelength of the incident radiation in angstroms.
_pd_background.Debye_diffuse_displace_su
CIF
Standard uncertainty of _pd_background.Debye_diffuse_displace.
_pd_background.Debye_diffuse_dist
CIF
The value of the distance in a Debye diffuse scattering equation representing the background in a calculated diffractogram.
The background equation is of the form
bkg = amplitude * sinc(distance * q) * exp(-displacement * q^2^)
where sinc(X) is defined as
sinc(X) = sin(X) / X
and where q is the magnitude of the diffraction vector, defined as
q = 4 * Pi * sin(theta) / lambda
where theta is the diffraction angle and lambda is the wavelength of the incident radiation in angstroms.
_pd_background.Debye_diffuse_dist_su
CIF
Standard uncertainty of _pd_background.Debye_diffuse_dist.
_pd_background.diffractogram_id
CIF
A diffractogram id to which the background equation relates.
_pd_background.id
CIF
An arbitrary code identifying part of a background equation.
_pd_background.line_segment_intensities
CIF
List of intensities used to create many straight-line segments representing the background in a calculated diffractogram.
See _pd_background.line_segment_intensity.
Must be in the same order as the X-coordinate values in
_pd_background.line_segment_Xs.
_pd_background.line_segment_intensities_su
CIF
Standard uncertainty of _pd_background.line_segment_intensities.
_pd_background.line_segment_intensity
CIF
The Y coordinate in an X,Y coordinate pair representing an X coordinate as defined in _pd_background.X_coordinate and intensity on the same scale as the calculated diffractogram intensities. Must be given with a value of _pd_background.line_segment_X to create a valid X,Y coordinate pair.
It is intended that at least two X,Y coordinate pairs are given, and that the line segments between them form the background function.
The value of the background function at a point x, is of the form:
(intensity_2 - intensity_1) bkg = --------------------------- * (x - X_1) + intensity_1 (X_2 - X_1)
where the X-coordinate is the coordinate in which the diffractogram was
calculated, and the function is defined only over the range X_1:X_2,
where X_1 and X_2 are taken as the closest values of
_pd_background.line_segment_X to the given x value, and intensity_1 and
intensity_2 are their associated intensity values.
_pd_background.line_segment_intensity_su
CIF
Standard uncertainty of _pd_background.line_segment_intensity.
_pd_background.line_segment_X
CIF
The X-coordinate in an X,Y coordinate pair representing an X coordinate as defined in _pd_background.X_coordinate and intensity on the same scale as the calculated diffractogram intensities. Must be given with a value of _pd_background.line_segment_intensity to create a valid X,Y coordinate pair.
It is intended that at least two X,Y coordinate pairs are given, and that the line segments between them form the background function.
The value of the background function at a point x, is of the form:
(intensity_2 - intensity_1) bkg = --------------------------- * (x - X_1) + intensity_1 (X_2 - X_1)
where the X-coordinate is the coordinate in which the diffractogram was
calculated, and the function is defined only over the range X_1:X_2,
where X_1 and X_2 are taken as the closest values of
_pd_background.line_segment_X to the given x value, and intensity_1 and
intensity_2 are their associated intensity values.
_pd_background.line_segment_Xs
CIF
List of X-coordinates used to create many straight-line segments representing the background in a calculated diffractogram.
See _pd_background.line_segment_X.
Must be in the same order as the intensity values in
_pd_background.line_segment_intensities.
_pd_background.peak_id
CIF
An arbitrary code is assigned to a peak in the background.
Used to link with _pd_peak.id. Each peak will have a unique code. In cases
where two peaks are severely overlapped, it may be desirable to list them as
a single peak.
A peak ID must be included for every amorphous peak.
_pd_background.polynomial_coef
CIF
The value of a coefficient used in a polynomial equation representing the
background in a calculated diffractogram. Must be given with a
_pd_background.polynomial_power value.
The background equation is of the form:
bkg = Sum( coeff * X_coord ^ power)
where the X-coordinate is coordinate in which the diffractogram was
calculated.
_pd_background.polynomial_coef_su
CIF
Standard uncertainty of _pd_background.polynomial_coef.
_pd_background.polynomial_coefs
CIF
List of coefficients used in a polynomial equation representing the background in a calculated diffractogram.
See _pd_background.polynomial_coef.
Must be in the same order as the powers in
_pd_background.polynomial_powers. Values at the same index in each list
are corresponding coefficient-power pairs.
_pd_background.polynomial_coefs_su
CIF
Standard uncertainty of _pd_background.polynomial_coefs.
_pd_background.polynomial_power
CIF
The value of a power used in a polynomial equation representing the background in a calculated diffractogram. Must be given with a _pd_background.polynomial_coeff value.
The background equation is of the form:
bkg = Sum( coeff * X_coord ^ power)
where the X-coordinate is coordinate in which the diffractogram was
calculated.
_pd_background.polynomial_power_su
CIF
Standard uncertainty of _pd_background.polynomial_power.
_pd_background.polynomial_powers
CIF
List of powers used in a polynomial equation representing the background in a calculated diffractogram.
See _pd_background.polynomial_power.
Must be in the same order as the powers in _pd_background.polynomial_coeff_list. Values at the same index in each list are corresponding coefficient-power pairs.
_pd_background.polynomial_powers_su
CIF
Standard uncertainty of _pd_background.polynomial_powers.
_pd_background.special_details
CIF
Description of background details that cannot otherwise be recorded using other PD_BACKGROUND data items.
_pd_background.X_coordinate
CIF
The type of X-coordinate against which the PD_BACKGROUND values were calculated where the explicit X-coordinate type of the background data item is not given.
If the background data item explicitly states with which X-coordinate it is calculated, then that takes precedence over any value here.
PD_BLOCK
CIF
_pd_block.id is used to assign a unique ID code to a data block. This code is then used for references between different blocks (see _pd_block_diffractogram.id, _pd_qpa_external_std.block_id and _pd_phase.block_id).
Note that a data block may contain only a single diffraction data set or information about a single crystalline phase. However, a single diffraction measurement may yield structural information on more than one phase, or a single structure determination may use more than one data set. Alternatively, results from a single data set, such as calibration parameters from measurements of a standard, may be used for many subsequent analyses. Through use of the ID code, a reference made between data sets may be preserved when the file is exported from the laboratory from which the CIF originated.
The ID code assigned to each data block should be unique with respect to an ID code assigned for any other data block in the world. The naming scheme chosen for the block-ID format is designed to ensure uniqueness.
It is the responsibility of a data archive site or local laboratory to create a catalogue of block IDs if that site wishes to resolve these references.
_pd_block.id
CIF
Used to assign a unique character string to a block. Note that this code is not intended to be parsed; the concatenation of several strings is used in order to generate a string that can reasonably be expected to be unique.
This code is assigned by the originator of the data set and is used for references between different CIF blocks. The ID will normally be created when the block is first created. It is possible to loop more than one ID for a block: if changes or additions are made to the block later, a new ID may be assigned, but the original name should be retained.
The suggested format for the ID code is:
<date-time>|<block_name>|<creator_name>|<instr_name>
<date-time> is the date and time the CIF was created or modified.
<block_name> is an arbitrary name assigned by the originator of the data set. It will usually match the name of the phase and possibly the name of the current CIF data block (i.e. the string xxxx in a data_xxxx identifier). It may be a sample name.
<creator_name> is the name of the person who measured the diffractogram, or prepared or modified the CIF.
<instr_name> is a unique name (as far as possible) for the data-collection instrument, preferably containing the instrument serial number for commercial instruments. It is also possible to use the Internet name or address for the instrument computer as a unique name.
As blocks are created in a CIF, the original sample identifier (i.e. <block_name>) should be retained, but the <creator_name> may be changed and the <date-time> will always change. The <date-time> will usually match either the _pd_meas.datetime_initiated or the _pd_proc.info_datetime entry.
Within each section of the code, the following characters may be used: A-Z a-z 0-9 # & * . : , - _ + / ( ) \ [ ]
The sections are separated with vertical rules '|' which are not allowed within the sections. Blank spaces may also not be used. Capitalization may be used within the ID code but should not be considered significant - searches for data-set ID names should be case-insensitive.
Date-time entries follow the standard RFC 3339 ABNF format 'yyyy-mm-ddThh:mm:ss{Z|[+-]zz:zz}'.
An archive site that wishes to make CIFs available via the web may substitute the URL for the file containing the appropriate block for the final two sections of the ID (<creator_name> and <instr_name>). Note that this should not be done unless the archive site is prepared to keep the file available online indefinitely.
Also known as: _pd_block_id
Examples:
1991-15-09T16:54:00Z|Si-std|B.Toby|D500#1234-987
1991-15-09T16:54:00Z|SEPD7234|B.Toby|SEPD.IPNS.ANL.GOV
PD_BLOCK_DIFFRACTOGRAM
CIF
A number of diffractograms may contribute to the determination of the structure of a single phase. The _pd_block.ids of those diffractograms should be listed here.
_pd_block_diffractogram.diffractogram_id
CIF
A diffractogram id code (see _pd_diffractogram.id) that identifies the diffraction data contained in the data block pointed to by _pd_block_diffractogram.id.
_pd_block_diffractogram.id
CIF
A block ID code (see _pd_block.id) that identifies diffraction data contained in a data block other than the current block. This will occur most frequently when more than one set of diffraction data is used for a structure determination. The data block containing the diffraction data will contain a _pd_block.id code matching the code in _pd_block_diffractogram.id.
Also known as: _pd_block_diffractogram_id
PD_CALC_COMPONENT
CIF
This section is used for storing the phase-specific components of a computed diffractogram, such as intensities calculated from a Rietveld refinement.
Example:
_pd_phase.id A_PHASE _pd_diffractogram.id A_DIFFRACTOGRAM
loop_ _pd_calc_component.point_id _pd_calc_component.intensity_total 0 25.994961 1 26.200290 2 26.404083 # further calculated points...
_pd_calc_component.block_id
CIF
A block ID code (see _pd_block.id) that identifies calculated component diffraction data contained in a data block other than the current block. The data block containing the crystallographic information for this phase will be identified with a _pd_block.id code matching the code in _pd_phase_block.id. The data block containing the diffractogram to which this component belongs will be identified with a _pd_block.id code matching the code in _pd_block_diffractogram.id.
_pd_calc_component.diffractogram_id
CIF
The diffractogram(s) (see _pd_diffractogram.id) to which these component intensities form part of the _pd_calc.intensity_total or _pd_calc.intensity_net values.
_pd_calc_component.intensity_net
CIF
Intensity values for the contribution of a phase to a computed diffractogram for each data point. Values should be computed at the same locations as the processed diffractogram, and thus the numbers of points will be defined by _pd_proc.number_of_points. Point positions may be defined using _pd_proc.2theta_range_*, _pd_proc.2theta_corrected, _pd_proc.d_spacing, or other appropriate x-coordinates.
Use _pd_calc_component.intensity_net if the computed component contribution diffraction pattern does not include background or normalization corrections and thus is specified on the same scale as the _pd_proc.intensity_net values.
In order to properly associate data between loops, _pd_calc_component.intensity_net must be looped with _pd_calc_component.point_id, and the measured/processed/calculated data must be looped with _pd_data.point_id.
_pd_calc_component.intensity_total
CIF
Intensity values for the contribution of a phase to a computed diffractogram for each data point. Values should be computed at the same locations as the processed diffractogram, and thus the numbers of points will be defined by _pd_proc.number_of_points. Point positions may be defined using _pd_proc.2theta_range_*, _pd_proc.2theta_corrected, _pd_proc.d_spacing, or other appropriate x-coordinates.
Use _pd_calc_component.intensity_total if the computed
component contribution diffraction pattern includes background
or normalization corrections (or both) and thus is specified on
the same scale as the observed intensities (_pd_meas.counts_*
or _pd_meas.intensity_*).
In order to properly associate data between loops, _pd_calc_component.intensity_net must be looped with _pd_calc_component.point_id, and the measured/processed/calculated data must be looped with _pd_data.point_id.
_pd_calc_component.phase_id
CIF
The phase (see _pd_phase.id) from which the component intensities
were calculated.
_pd_calc_component.point_id
CIF
Arbitrary label identifying a calculated component data point. Used to identify a specific entry in a list of values forming the calculated component diffractogram.
The value of _pd_calc_component.point_id must be the same as the value of _pd_data.point_id given to the equivalent data point in the measured/processed/calculated diffractogram to which this component belongs.
PD_CALC_OVERALL
CIF
Items in this category record overall features of the computed diffractogram.
_pd_calc.method
CIF
A description of the method used for the calculation of the intensities in _pd_calc.intensity_*. If the pattern was calculated from crystal structure data for a single phase, the atom coordinates and other crystallographic information should be included in the datablock using the core CIF ATOM_SITE and CELL data items. If multiple phases were used, these should be listed in the pd_phase category.
Also known as: _pd_calc_method
Examples:
Rietveld
Pawley
Le Bail
Independent peak fitting
_pd_calc_overall.component_presentation_order
CIF
List of _pd_phase.ids specifying the order in which the individual phases' calculated components are given within _pd_calc.component_intensity_*_list.
_pd_calc_overall.diffractogram_id
CIF
The diffractogram (see _pd_diffractogram.id) to which the associated
features relate.
PD_CALIB
CIF
This section defines the parameters used for the calibration of the instrument that are used directly or indirectly in the interpretation of this data set. The information in this section of the CIF should generally be written when the intensities are first measured, but from then on should remain unchanged. Loops may be used for calibration information that differs by detector channel.
_pd_calib.detector_id
CIF
A code which identifies the detector or channel number in a
position-sensitive, energy-dispersive or other multiple-detector
instrument. Note that this code should match the code name used
for _pd_meas.detector_id.
Also known as: _pd_calib_detector_id
_pd_calib.detector_response
CIF
A value that indicates the relative sensitivity of each detector. This can compensate for differences in electronics, size and collimation. Usually, one detector or the mean for all detectors will be assigned the value of 1.
Also known as: _pd_calib_detector_response
_pd_calib.detector_response_su
CIF
Standard uncertainty of _pd_calib.detector_response.
_pd_calib.std_internal_mass_percent
CIF
This item is deprecated. Please see _pd_qpa_internal_std.mass_percent.
Per cent presence of the internal standard specified by the
data item _pd_calib.std_internal_name expressed as 100 times
the mass of standard added divided by the sum of the mass of
standard added and the original sample mass.
_pd_calib.std_internal_mass_percent_su
CIF
This item is deprecated. Please see _pd_qpa_internal_std.mass_percent_su.
Standard uncertainty of _pd_calib.std_internal_mass_percent.
_pd_calib.std_internal_name
CIF
Identity of material(s) used as an internal intensity standard.
Also known as: _pd_calib_std_internal_name
Examples:
NIST 640a Silicon standard
Al2O3
PD_CALIBRATION
CIF
This section contains calibration information that is not looped
_pd_calibration.conversion_eqn
CIF
The calibration function for converting a channel number supplied in _pd_meas.detector_id for a position-sensitive or energy-dispersive detector or the distance supplied in _pd_meas.position to Q, energy, angle etc.
Use _pd_calib_std.external_block_id to define a pointer to
the data block containing the data used to determine the
parameter values in this function.
Also known as: _pd_calibration_conversion_eqn
Example:
2~actual~ = 2~setting~ + arctan( cos(P~1~) / {1/[P~0~ (CC - CH~0~ - P~2~ CC^2^)] - sin(P~1~)})
_pd_calibration.special_details
CIF
Description of how the instrument was calibrated, particularly for instruments where calibration information is used to make hardware settings that would otherwise be invisible once data collection is completed. Do not use this item to specify information that can be specified using other PD_CALIBRATION or PD_CALIB items.
Also known as: _pd_calibration_special_details
PD_CALIB_DETECTED_INTENSITY
CIF
This section defines the parameters used for the intensity calibration of the detectors which are used directly or indirectly in the interpretation of this data set. The information in this section of the CIF should generally be written when the intensities are first measured, but from then on should remain unchanged. Loops may be used for calibration information that differs by detector channel or ID.
Common intensity calibration procedures include, but are not limited to:
i) the application of a known, uniform, flood-field; or ii) scanning a detector bank across a peak, or the direct-beam.
The above examples provide experimental methods to assign values to _pd_calib_intensity.detector_response, to place each detector on a common scale. Note that these are only indicative examples.
This category is only intended to record detector-related response to a beam incident on the detector. To record variations in intensity during the measurement of a diffractogram, see _pd_meas.intensity_monitor and _pd_meas.counts_monitor.
_pd_calib_detected_intensity.block_id
CIF
A block ID code identifying the diffractogram from which the intensity calibration was taken, if it was calibrated by a specimen.
The data block containing the diffraction pattern will be identified with a
_pd_block.id code matching the code in _pd_calib_intensity.block_id.
_pd_calib_detected_intensity.detector_id
CIF
A code which identifies the detector or channel number in a
position-sensitive, energy-dispersive or other multiple-detector instrument.
Note that this code should match the code name used for
_pd_meas.detector_id.
_pd_calib_detected_intensity.detector_response
CIF
A value that indicates the relative sensitivity of each detector. That is, a
value of 0.5 indicates that the detector records half as much intensity as
it should, and a value of 2 indicates that the detector records twice as
much intensity as it should. To bring all detectors on to a common scale,
the observed intensity should be divided by the value of
_pd_calib_detected_intensity.detector_response
This can compensate for differences in electronics, size and collimation. Usually, one detector, or the mean for all detectors, will be assigned the value of 1.
_pd_calib_detected_intensity.detector_response_su
CIF
Standard uncertainty of _pd_calib_detected_intensity.detector_response.
_pd_calib_detected_intensity.diffractogram_id
CIF
A code which identifies the particular diffractogram from which this intensity calibration was taken, if it was calibrated by a specimen.
_pd_calib_detected_intensity.id
CIF
A code to uniquely identify each intensity calibration.
_pd_calib_detected_intensity.phase_id
CIF
A code which identifies the particular phase from which this intensity was taken, if it was calibrated by a specimen.
_pd_calib_detected_intensity.special_details
CIF
Description of detected intensity calibration details that cannot otherwise be recorded using other PD_CALIB_DETECTED_INTENSITY data items
PD_CALIB_D_TO_TOF
CIF
This section defines the parameters used for the calibration of time-of-flight from d-spacing for neutron data.
The calibration equation is of the form:
TOF = sum_i [ c_i * d^p_i ]
where TOF is the time-of-flight in microseconds, d is the d-spacing in angstroms, c_i is the ith coefficient, and p_i is the ith power.
A loop is used to specify all terms of the correction per histogram.
Examples:
loop_ _pd_calib_d_to_tof.id _pd_calib_d_to_tof.power _pd_calib_d_to_tof.coeff 0 0 -2.062 DIFC 1 746.8 t2 2 0.08099
loop_ _pd_calib_d_to_tof.id _pd_calib_d_to_tof.power _pd_calib_d_to_tof.coeff _pd_calib_d_to_tof.coeff_su 0 0 -2.062 2.09 DIFC 1 746.8 1.14 t2 2 0.08099 0.102 DIFB -1 0.00232 0.0013
_pd_calib_d_to_tof.coeff
CIF
The value of the coefficient used in the equation to convert d-spacing into time-of-flight.
_pd_calib_d_to_tof.coeff_su
CIF
Standard uncertainty of _pd_calib_d_to_tof.coeff.
_pd_calib_d_to_tof.diffractogram_id
CIF
The diffractogram (see _pd_diffractogram.id) to which the calibration
relates.
_pd_calib_d_to_tof.id
CIF
An arbitrary code which identifies a specific term of the calibration equation.
_pd_calib_d_to_tof.power
CIF
The value of the power used in the equation to convert d-spacing into time-of-flight.
PD_CALIB_INCIDENT_INTENSITY
CIF
This section defines the parameters used for the incident intensity calibration of the instrument which is used directly or indirectly in the interpretation of this data set. The information in this section of the CIF should generally be written when the intensities are first measured, but from then on should remain unchanged.
One common intensity calibration procedures involves data collection from a standard amount of crystalline sample, which allows a value to be assigned to _pd_calib_intensity.incident_intensity, to place different diffractograms on a common scale. Note that this is only an indicative example.
_pd_calib_incident_intensity.block_id
CIF
A block ID code identifying the diffractogram from which the intensity calibration was taken, if it was calibrated by a specimen.
The data block containing the diffraction pattern will be identified with a _pd_block.id code matching the code in _pd_calib_incident_intensity.block_id.
_pd_calib_incident_intensity.diffractogram_id
CIF
A code which identifies the particular diffractogram from which this intensity calibration was taken, if it was calibrated by a specimen.
_pd_calib_incident_intensity.id
CIF
A code to uniquely identify each incident intensity calibration.
_pd_calib_incident_intensity.incident_counts
CIF
A value that indicates the number of counts incident on the specimen. This
value is be a constant for each diffractgram. For point-wise corrections,
see _pd_meas.counts_monitor.
Standard uncertainties should not be quoted for this value. If the standard uncertainties differ from the square root of the number of counts, _pd_calib_intensity.incident_intensity should be used.
_pd_calib_incident_intensity.incident_intensity
CIF
A value that indicates the intensity incident on the specimen. This value
is a constant for each diffractgram. For point-wise corrections, see
_pd_meas.intensity_monitor.
Use this entry for measurements where intensity values are not counts (use _pd_calib_intensity.incident_counts for event-counting measurements, where the standard uncertainty is estimated as the square root of the number of counts).
_pd_calib_incident_intensity.incident_intensity_su
CIF
Standard uncertainty of _pd_calib_incident_intensity.incident_intensity.
_pd_calib_incident_intensity.phase_id
CIF
A code which identifies the particular phase from which this intensity was taken, if it was calibrated by a specimen.
_pd_calib_incident_intensity.special_details
CIF
Description of intensity calibration details that cannot otherwise be recorded using other PD_CALIB_INCIDENT_INTENSITY data items
PD_CALIB_OFFSET
CIF
Data items in this category define an offset angle (in degrees) used to calibrate 2 (as defined in _pd_meas.2theta_*). Calibration is done by adding the offset:
2~calibrated~ = 2~measured~ + 2~offset~
For cases where the _pd_calib.2theta_offset value is
not a constant, but rather varies with 2, a set
of offset values is supplied in a loop. In this case,
the value where the offset has been determined can be
specified as _pd_calib.2theta_off_point. Alternatively, a
range where the offset is applicable can be specified using
_pd_calib.2theta_off_min and _pd_calib.2theta_off_max.
_pd_calib.2theta_off_max
CIF
The maximum nominal 2 value to which the offset given by
_pd_calib.2theta_offset applies.
Also known as: _pd_calib_2theta_off_max
_pd_calib.2theta_off_min
CIF
The minimum nominal 2 value to which the offset given by
_pd_calib.2theta_offset applies.
Also known as: _pd_calib_2theta_off_min
_pd_calib.2theta_off_point
CIF
The nominal 2 value to which the offset given in
_pd_calib.2theta_offset applies.
Also known as: _pd_calib_2theta_off_point
_pd_calib.2theta_offset
CIF
_pd_calib.2theta_offset defines an offset angle (in degrees)
used to calibrate 2 (as defined in _pd_meas.2theta_*).
Calibration is done by adding the offset:
2~calibrated~ = 2~measured~ + 2~offset~
Also known as: _pd_calib_2theta_offset
_pd_calib.2theta_offset_su
CIF
Standard uncertainty of _pd_calib.2theta_offset.
_pd_calib_offset.detector_id
CIF
The detector to which the offset values relate. As a default value is defined, the detector id may be omitted if only a single detector is present.
_pd_calib_offset.id
CIF
An arbitrary code which identifies a particular 2 offset description. As a default value is defined, this may be omitted if only a single offset is provided.
PD_CALIB_STD
CIF
This category identifies the external standards used for the calibration of the instrument that are used directly or indirectly in the interpretation of this data set. The information in this section of the CIF should generally be written when the intensities are first measured, but from then on should remain unchanged. Loops may be used for calibration information that differs by detector channel or when multiple standards are used (for example, separately for angular and gain calibration).
For quantitative phase analysis by the external standard approach, please see PD_QPA_EXT_STD.
_pd_calib_std.detector_id
CIF
A code which identifies the detector or channel number that the
calibration data applies to. Note that this code should match a
detector from _pd_meas.detector_id and may be omitted if only
one detector is used.
_pd_calib_std.external_block_id
CIF
Identifies the _pd_block.id used as an external standard for the
diffraction angle or the intensity calibrations.
For quantitative phase analysis by the external standard approach, please see PD_QPA_EXT_STD.
Also known as: _pd_calib_std_external_block_id
_pd_calib_std.external_name
CIF
Identifies the name of the material used as an external standard for the diffraction angle or the intensity calibrations.
Also known as: _pd_calib_std_external_name
PD_CALIB_WAVELENGTH
CIF
This category allows for linking to the diffractograms and phases used in the calibration of the wavelength used directly or indirectly in the interpretation of this data set.
Loops may be used when multiple phases and/or diffractograms are used for calibration. In this case, the given wavelength is a best-fit to all phases and diffractograms.
See also _diffrn_radiation_wavelength.determination.
Examples:
_audit.schema Custom
loop_ _pd_calib_wavelength.diffrn_id _pd_calib_wavelength.diffractogram_id _pd_calib_wavelength.phase_id DIFFRN_EXP_1 DIFFRACTOGRAM_1 NIST_SILICON DIFFRN_EXP_1 DIFFRACTOGRAM_1 NIST_LAB6 DIFFRN_EXP_1 DIFFRACTOGRAM_2 NIST_SILICON DIFFRN_EXP_1 DIFFRACTOGRAM_2 NIST_LAB6
_diffrn.id DIFFRN_EXP_A _pd_calib_wavelength.diffractogram_id DIFFRACTOGRAM_A _pd_calib_wavelength.phase_id ACME_CORUNDUM
_pd_calib_wavelength.block_id
CIF
A block ID code for a block containing a diffractogram used to calibrate the wavelength.
The data block containing the diffraction pattern will be identified with a _pd_block.id code matching the code in _pd_calib_wavelength.block_id.
_pd_calib_wavelength.diffractogram_id
CIF
A code which identifies a diffractogram which was used in the calibration of the wavelength.
_pd_calib_wavelength.diffrn_id
CIF
A code which identifies the diffraction experiment to which this calibration belongs.
_pd_calib_wavelength.phase_id
CIF
A code which identifies a phase whose cell parameters were used in the calibration of the wavelength.
_pd_calib_wavelength.special_details
CIF
Description of intensity calibration details that cannot otherwise be recorded using other PD_CALIB_WAVELENGTH data items
PD_CHAR
CIF
This section contains experimental (non-diffraction) information relevant to the chemical and physical nature of the material from which the sample is drawn.
'Specimen', 'sample', and 'material' have specific meanings, and sometimes cannot be specifically deliniated. The 'specimen' is the artefact placed into the beam from which the diffraction measurement is taken, and is described in PD_SPEC. The specimen is made from the 'sample', which can have information is specified in PD_PREP. The sample is drawn from a 'material', which may exist in an actual or idealised sense, which can have information is specified in PD_CHAR. For example: the material might be BaTiO3, the sample might be a specific batch from a specific manufacturer, and the specimen is the material taken from the bottle and placed in the instrument.
_pd_char.atten_coef_mu_calc
CIF
The calculated linear attenuation coefficient, , in units
of inverse millimetres, also known as the linear absorption
coefficient. The value is obtained from the atomic content of
each of the phases in the material, the average density
(allowing for packing density), and the radiation wavelength.
Note that _pd_char.atten_coef_mu_calc will differ from the value
based on phase quantities and _exptl_absorpt.coefficient_mu for
each phase if the packing density is not unity.
Also known as: _pd_char_atten_coef_mu_calc
_pd_char.atten_coef_mu_calc_su
CIF
Standard uncertainty of _pd_char.atten_coef_mu_calc.
_pd_char.atten_coef_mu_obs
CIF
The observed linear attenuation coefficient, , in units of inverse millimetres, also known as the linear absorption coefficient. The value is determined by a transmission measurement.
Also known as: _pd_char_atten_coef_mu_obs
_pd_char.atten_coef_mu_obs_su
CIF
Standard uncertainty of _pd_char.atten_coef_mu_obs.
_pd_char.colour
CIF
The colour of the material used for the measurement. To facilitate more standardized use of names, the following guidelines for colour naming developed by Peter Bayliss for the International Centre for Diffraction Data (ICDD) should be followed. Note that combinations of descriptors are separated by an underscore.
Allowed colours are:
colourless, white, black, gray, brown, red, pink, orange, yellow, green, blue, violet.
Colours may be modified using prefixes of: light, dark, whitish, blackish, grayish, brownish, reddish, pinkish, orangish, yellowish, greenish, bluish.
Intermediate hues may be indicated with two colours: e.g. blue_green or bluish_green.
For metallic materials, the term metallic may be added: e.g. reddish_orange_metallic for copper.
The ICDD standard allows commas to be used for minerals that occur with ranges of colours; however this usage is not appropriate for the description of a single sample.
Also known as: _pd_char_colour
Examples:
dark_green
orange_red
brownish_red
yellow_metallic
_pd_char.mass_atten_coef_mu_calc
CIF
The calculated mass attenuation coefficient, ^*^, in units of square millimetres per gram, also known as the mass absorption coefficient. The calculated ^*^ will be obtained from the atomic content of each phase and the radiation wavelength.
_pd_char.mass_atten_coef_mu_calc_su
CIF
Standard uncertainty of _pd_char.mass_atten_coef_mu_calc.
_pd_char.mass_atten_coef_mu_meas
CIF
The measured mass attenuation coefficient, ^*^, in units of square millimetres per gram, also known as the mass absorption coefficient. The measured ^*^ will be normally be determined by a transmission measurement coupled with a density measurement.
_pd_char.mass_atten_coef_mu_meas_su
CIF
Standard uncertainty of _pd_char.mass_atten_coef_mu_meas.
_pd_char.particle_morphology
CIF
A description of the sample morphology and estimates for
particle sizes (before grinding/sieving, if noted by
_pd_spec.preparation). Include the method used for
these estimates (SEM, visual estimate etc.).
Also known as: _pd_char_particle_morphology
_pd_char.special_details
CIF
Additional characterization information relevant to the sample or documentation of non-routine processing steps used for characterization.
Also known as: _pd_char_special_details
PD_DATA
CIF
The PD_DATA category is a "container" category that is defined in order to allow raw, processed, and calculated data points in a diffraction data set to be optionally tabulated together. As PD_CALC, PD_MEAS, and PD_PROC are all subcategories of this category, the various items belonging to those categories may be looped together or separately, as desired.
Examples:
loop_ _pd_data.point_id _pd_meas.2theta_scan _pd_meas.intensity_total _pd_calc.intensity_total _pd_proc.intensity_bkg_calc 1 5.001 43.364 25.994961 25.994961 2 5.004 38.007 26.200290 26.200290 3 5.007 38.318 26.404083 26.404083 4 5.010 41.877 26.606346 26.606346 #further data points follow
loop_ _pd_data.point_id _pd_meas.time_of_flight _pd_proc.d_spacing _pd_proc.intensity_total _pd_proc_ls.weight _pd_calc.intensity_total _pd_proc.intensity_bkg_calc 0 1110.30100 1.489225 0.60008 6528.86960 0.553025 0.504217 1 1114.74220 1.495170 0.63531 6316.37917 0.571286 0.504020 2 1119.20117 1.501138 0.64690 6107.85715 0.593895 0.503826 3 1123.67798 1.507131 0.65580 6162.14696 0.620014 0.503635 4 1128.17269 1.513147 0.69097 5674.48379 0.647871 0.503449 #further data points follow
loop_ _pd_data.point_id _pd_meas.2theta_scan _pd_proc.2theta_corrected _pd_meas.intensity_total _pd_calc.intensity_total 0 3.99875 3.907132 1061.8 1076.653 1 4.03625 3.944633 1053.9 1074.628 2 4.07375 3.982134 1060.2 1072.667 3 4.11125 4.019635 1017.3 1070.768 #further data points follow
loop_ _pd_data.point_id _pd_meas.2theta_scan _pd_meas.counts_total 1 4.03 154 2 4.09 140 3 4.15 134 4 4.21 171 #further data points follow
_pd_data.diffractogram_id
CIF
Label identifying the diffraction measurement that the data tabulated in the PD_DATA category belong to. This may be omitted in the usual case that only one diffraction measurement is present in a data block.
_pd_data.point_id
CIF
Arbitrary label identifying an entry in the table of diffractogram intensity values. This should be used in preference to the pd_calc/pd_calc_component/pd_meas/pd_proc point_id data items whenever data items from more than one of the pd_calc/pd_calc_component/pd_proc/pd_meas categories are looped together.
Also known as: _pd_data_point_id
PD_CALC
CIF
This section is used for storing a computed diffractogram trace. This may be a simulated powder pattern for a material from a program such as LAZY/PULVERIX or the computed intensities from a Rietveld refinement.
_pd_calc.component_intensity_net_list
CIF
List of intensity values for the contributions of an arbitrary number of individual phases to a computed diffractogram for each data point. Values are listed in the order given by _pd_calc_overall.component_presentation_order. Values should be computed at the same locations as the processed diffractogram, and thus the numbers of points will be defined by _pd_proc.number_of_points. Point positions may be defined using _pd_proc.2theta_range_*, _pd_proc.2theta_corrected, _pd_proc.d_spacing, or other appropriate x-coordinates.
Use _pd_calc.component_intensity_net_list if the computed component contribution diffraction patterns do not include background or normalization corrections and thus are specified on the same scale as the _pd_proc.intensity_net values.
_pd_calc.component_intensity_*_list should be looped with
either _pd_proc.intensity_net, _pd_meas.counts_*, and/or
_pd_meas.intensity_*.
_pd_calc.component_intensity_total_list
CIF
List of intensity values for the contributions of an arbitrary number of individual phases to a computed diffractogram at each data point. Values are listed in the order given by _pd_calc_overall.component_presentation_order. Values should be computed at the same locations as the processed diffractogram, and thus the numbers of points will be defined by _pd_proc.number_of_points. Point positions may be defined using _pd_proc.2theta_range_*, _pd_proc.2theta_corrected, _pd_proc.d_spacing, or other appropriate x-coordinates.
Use _pd_calc.component_intensity_total_list if the computed
component contribution diffraction patterns include background
or normalization corrections (or both), and thus are specified
on the same scale as the observed intensities (_pd_meas.counts_*
or _pd_meas.intensity_*).
_pd_calc.component_intensity_*_list should be looped with
either _pd_proc.intensity_net, _pd_meas.counts_*, and/or
_pd_meas.intensity_*.
_pd_calc.diffractogram_id
CIF
Label identifying the calculated diffractogram that the calculated data belong to. This may be omitted in the usual case that only one calculation is present in a data block.
_pd_calc.intensity_net
CIF
Intensity values for a computed diffractogram at each data point. Values should be computed at the same locations as the processed diffractogram, and thus the numbers of points will be defined by _pd_proc.number_of_points and point positions may be defined using _pd_proc.2theta_range_* or _pd_proc.2theta_corrected.
Use _pd_calc.intensity_net if the computed diffractogram does not contain background or normalization corrections and thus is specified on the same scale as the _pd_proc.intensity_net values.
If an observed pattern is included, _pd_calc.intensity_*
should be looped with either _pd_proc.intensity_net,
_pd_meas.counts_* or _pd_meas.intensity_*.
Also known as: _pd_calc_intensity_net
_pd_calc.intensity_total
CIF
Intensity values for a computed diffractogram at each data point. Values should be computed at the same locations as the processed diffractogram, and thus the numbers of points will be defined by _pd_proc.number_of_points and point positions may be defined using _pd_proc.2theta_range_* or _pd_proc.2theta_corrected.
Use _pd_calc.intensity_total if the computed diffraction pattern includes background or normalization corrections (or both) and thus is specified on the same scale as the observed intensities (_pd_meas.counts_* or _pd_meas.intensity_*). If an observed pattern is included, _pd_calc.intensity_* should be looped with either _pd_proc.intensity_net, _pd_meas.counts_* or _pd_meas.intensity_*.
Also known as: _pd_calc_intensity_total
_pd_calc.point_id
CIF
Arbitrary label identifying a calculated data point. Used to
identify a specific entry in a list of values forming the
calculated diffractogram. The role of this identifier may
be adopted by _pd_data.point_id if measured, processed, and/or
calculated intensity values are combined in a single list.
Also known as: _pd_calc_point_id
PD_MEAS
CIF
This section contains the measured diffractogram prior to
processing and application of correction terms. While additional
information may be added to the CIF as data are processed and
transported between laboratories (possibly with the addition of
a new _pd_block.id entry), the information in this section of
the CIF will rarely be changed once data collection is complete.
Where possible, measurements in this section should have no post-collection processing applied (normalizations, corrections, smoothing, zero-offset corrections etc.). Such corrected measurements should be recorded in the PD_PROC section.
Data sets that are measured as counts, where a standard uncertainty can be considered equivalent to the standard deviation and where the standard deviation can be estimated as the square root of the number of counts recorded, should use the _pd_meas.counts_* fields. All other intensity values should be recorded using _pd_meas.intensity_*.
_pd_instr.dist_spec_vdetc
CIF
Distance from the specimen to the virtual detector (in millimetres). The virtual detector is point in space at which the detector is sampling the diffracted radiation from the point of view of the specimen. eg the specimen-receiving slit distance in a point-detector, Bragg-Brentano diffractometer. This distance is also referred to as the 'secondary radius', or the 'diffracted beam radius'.
Where the specimen-detector distance is difficult to define, for example, for a large, flat, area detector, the distance refers to the closest approach of the detector to the specimen.
See the discussion on 'detector circle' or 'goniometer circle' in International Tables Vol H, S2.1.4.1 for further information.
_pd_instr.dist_vsrc_spec
CIF
Distance from the virtual source to the specimen (in millimetres). The virtual source is point in space from which the incident radiation can be said to be coming from from the point of view of the specimen. This distance is also referred to as the 'primary radius', or the 'incident beam radius'.
See the discussion on 'detector circle' or 'goniometer circle' in International Tables Vol H, S2.1.4.1 for further information.
_pd_instr.var_illum_len
CIF
Length of the specimen that is illuminated by the radiation
source (in millimetres) for instruments where
the illumination length varies with 2 (fixed
divergence slits). The _pd_instr.var_illum_len
values should be included in the same loop as the
intensity measurements (_pd_meas.* items).
See _pd_instr.cons_illum_len for instruments where
the divergence slit is -compensated to yield a
constant illumination length.
Also known as: _pd_instr_var_illum_len
_pd_meas.2theta_scan
CIF
2 diffraction angle (in degrees) for intensity points measured in a scanning method. The scan method used (e.g. continuous or step scan) should be specified in the item _pd_meas.scan_method. For fixed 2 (white-beam) experiments, use _pd_meas.2theta_fixed. In the case of continuous-scan data sets, the 2 value should be the value at the midpoint of the counting period. Associated with each _pd_meas.2theta_scan value will be _pd_meas.counts_* items. The 2 values should not be corrected for nonlinearity, zero offset etc. Corrected values may be specified using _pd_proc.2theta_corrected.
Note that for data sets collected with constant step size,
_pd_meas.2theta_range_* (min, max and inc) may be used
instead of _pd_meas.2theta_scan. _pd_meas.2theta_angle was
originally a distinct but cognate definition and should not be
used in new files.
_pd_meas.2theta_scan_su
CIF
Standard uncertainty of _pd_meas.2theta_scan.
_pd_meas.counts_background
CIF
Counts recorded at each measurement point as a function of angle, time, channel, or some other variable (see _pd_meas.2theta_* etc.). These counts are measured without a specimen, specimen mounting etc., often referred to as the instrument background.
Corrections for background, detector dead time etc.
should not have been made to these values. Instead, make the
corrections and record the result using
_pd_proc.intensity_net, _norm, or _total, as appropriate,
for corrected diffractograms.
Note that counts-per-second values should be converted to
total counts. If the counting time varies for different
points, it may be included in the loop using
_pd_meas.step_count_time.
Standard uncertainties should not be quoted for these values. If the standard uncertainties differ from the square root of the number of counts, _pd_meas.intensity_* should be used.
Also known as: _pd_meas_counts_background
_pd_meas.counts_container
CIF
Counts recorded at each measurement point as a function of angle, time, channel, or some other variable (see _pd_meas.2theta_* etc.). These counts are measured from a specimen container or mounting without a specimen, includes background.
Corrections for background, detector dead time etc. should not have been made to these values. Instead use _pd_proc.intensity_* for corrected diffractograms.
Note that counts-per-second values should be converted to
total counts. If the counting time varies for different
points, it may be included in the loop using
_pd_meas.step_count_time.
Standard uncertainties should not be quoted for these values. If the standard uncertainties differ from the square root of the number of counts, _pd_meas.intensity_* should be used.
Also known as: _pd_meas_counts_container
_pd_meas.counts_monitor
CIF
Counts recorded at each measurement point as a function of angle, time, channel, or some other variable (see _pd_meas.2theta_* etc.). These counts are measured by an incident-beam monitor to calibrate the flux on the specimen.
Corrections for background, detector dead time etc. should not have been made to these values. Instead use _pd_proc.intensity_* for corrected diffractograms.
Note that counts-per-second values should be converted to
total counts. If the counting time varies for different
points, it may be included in the loop using
_pd_meas.step_count_time.
Standard uncertainties should not be quoted for these values. If the standard uncertainties differ from the square root of the number of counts, _pd_meas.intensity_* should be used.
Also known as: _pd_meas_counts_monitor
_pd_meas.counts_total
CIF
Counts recorded at each measurement point as a function of angle, time, channel, or some other variable (see _pd_meas.2theta_* etc.). These counts are measured from the specimen with background, specimen mounting, and/or container scattering included.
Corrections for background, detector dead time etc. should not have been made to these values. Instead use _pd_proc.intensity_* for corrected diffractograms.
Note that counts-per-second values should be converted to
total counts. If the counting time varies for different
points, it may be included in the loop using
_pd_meas.step_count_time.
Standard uncertainties should not be quoted for these values. If the standard uncertainties differ from the square root of the number of counts, _pd_meas.intensity_* should be used.
Also known as: _pd_meas_counts_total
_pd_meas.detector_id
CIF
A code or number which identifies the measuring detector or channel number in a position-sensitive, energy-dispersive or other multiple-detector instrument.
Calibration information, such as angle offsets or
a calibration function to convert channel numbers
to Q, energy, wavelength, angle etc. should
be described with PD_CALIB values. If
_pd_calibration.conversion_eqn is used, the detector ID's
should be the number to be used in the equation.
Also known as: _pd_meas_detector_id
_pd_meas.diffractogram_id
CIF
Label identifying the diffraction measurement that the data tabulated in the PD_MEAS category belong to. This may be omitted in the usual case that only one diffraction measurement is present in a data block.
_pd_meas.intensity_background
CIF
Intensity recorded at each measurement point as a function of angle, time, channel, or some other variable (see _pd_meas.2theta_* etc.). These intensities are measured without a specimen, specimen mounting etc., often referred to as the instrument background.
Use these entries for measurements where intensity values are not counts (use _pd_meas.counts_* for event-counting measurements where the standard uncertainty is estimated as the square root of the number of counts).
Corrections for background, detector dead time etc.
should not have been made to these values. Instead, make the
corrections and record the result using
_pd_proc.intensity_net, _norm, or _total, as appropriate,
for corrected diffractograms.
_pd_meas.units_of_intensity should be used to specify
the units of the intensity measurements.
Also known as: _pd_meas_intensity_background
_pd_meas.intensity_background_su
CIF
Standard uncertainty of _pd_meas.intensity_background.
_pd_meas.intensity_container
CIF
Intensity recorded at each measurement point as a function of angle, time, channel, or some other variable (see _pd_meas.2theta_* etc.). These intensities are measured from the specimen container or mounting without a specimen, includes background.
Use these entries for measurements where intensity values are not counts (use _pd_meas.counts_* for event-counting measurements where the standard uncertainty is estimated as the square root of the number of counts).
Corrections for background, detector dead time etc.
should not have been made to these values. Instead, make the
corrections and record the result using
_pd_proc.intensity_net, _norm, or _total, as appropriate,
for corrected diffractograms.
_pd_meas.units_of_intensity should be used to specify
the units of the intensity measurements.
Also known as: _pd_meas_intensity_container
_pd_meas.intensity_container_su
CIF
Standard uncertainty of _pd_meas.intensity_container.
_pd_meas.intensity_monitor
CIF
Intensity recorded at each measurement point as a function of angle, time, channel, or some other variable (see _pd_meas.2theta_* etc.). These intensities are measured by an incident-beam monitor to calibrate the flux on the specimen. For a single value used to scale an entire diffractogram, see _pd_calib_intensity.incident_intensity.
Use these entries for measurements where intensity values are not counts (use _pd_meas.counts_* for event-counting measurements where the standard uncertainty is estimated as the square root of the number of counts).
Corrections for background, detector dead time etc.
should not have been made to these values. Instead, make the
corrections and record the result using
_pd_proc.intensity_net, _norm, or _total, as appropriate,
for corrected diffractograms.
_pd_meas.units_of_intensity should be used to specify
the units of the intensity measurements.
Also known as: _pd_meas_intensity_monitor
_pd_meas.intensity_monitor_su
CIF
Standard uncertainty of _pd_meas.intensity_monitor.
_pd_meas.intensity_total
CIF
Intensity recorded at each measurement point as a function of angle, time, channel, or some other variable (see _pd_meas.2theta_* etc.). These intensities are measured from the specimen, with background, specimen mounting, and/or container scattering included.
Use these entries for measurements where intensity values are not counts (use _pd_meas.counts_* for event-counting measurements where the standard uncertainty is estimated as the square root of the number of counts).
Corrections for background, detector dead time etc., should not have been made to these values. Instead use _pd_proc.intensity_* for corrected diffractograms.
_pd_meas.units_of_intensity should be used to specify
the units of the intensity measurements.
Also known as: _pd_meas_intensity_total
_pd_meas.intensity_total_su
CIF
Standard uncertainty of _pd_meas.intensity_total.
_pd_meas.point_id
CIF
Arbitrary label identifying a measured data point. Used to
identify a specific entry in a list of measured intensities.
The role of this identifier may be adopted by
_pd_data.point_id if measured, processed, and/or calculated
intensity values are combined in a single list.
Also known as: _pd_meas_point_id
_pd_meas.position
CIF
A linear distance in millimetres corresponding to the location where an intensity measurement is made. Used for detectors where a distance measurement is made as a direct observable, such as from a microdensitometer trace from film or a strip chart recorder. This is an alternative to _pd_meas.2theta_scan, which should only be used for instruments that record intensities directly against 2. For instruments where the position scale is nonlinear, the data item _pd_meas.detector_id should be used to record positions.
Calibration information, such as angle offsets or a function to convert this distance to a 2 angle or d-space, should be supplied with items from PD_CALIB.
Do not confuse this with the instrument geometry descriptions given by _pd_instr.dist_*.
Also known as: _pd_meas_position
_pd_meas.position_su
CIF
Standard uncertainty of _pd_meas.position.
_pd_meas.step_count_time
CIF
The count time in seconds for each intensity measurement.
Also known as: _pd_meas_step_count_time
_pd_meas.step_count_time_su
CIF
Standard uncertainty of _pd_meas.step_count_time.
_pd_meas.time_of_flight
CIF
Measured time in microseconds for time-of-flight neutron measurements. Note that the flight distance may be specified using _pd_instr.dist_* values.
Also known as: _pd_meas_time_of_flight
_pd_meas.time_of_flight_su
CIF
Standard uncertainty of _pd_meas.time_of_flight.
PD_PROC
CIF
This section contains the diffraction data set after processing
and application of correction terms. If the data set is
reprocessed, this section may be replaced (with the addition of
a new _pd_block.id entry).
_pd_proc.2theta_corrected
CIF
The 2 diffraction angle in degrees of an intensity measurement where 2 is not constant. Used if corrections such as for nonlinearity, zero offset etc. have been applied to the _pd_meas.2theta_* values or if 2 values are computed. If the 2 values are evenly spaced, _pd_proc.2theta_range_min, _pd_proc.2theta_range_max and _pd_proc.2theta_range_inc may be used to specify the 2 values.
Also known as: _pd_proc_2theta_corrected
_pd_proc.2theta_corrected_su
CIF
Standard uncertainty of _pd_proc.2theta_corrected.
_pd_proc.d_spacing
CIF
d-spacing corresponding to an intensity point from Bragg's law, d = /(2 sin), in units of angstroms.
Also known as: _pd_proc_d_spacing
_pd_proc.d_spacing_su
CIF
Standard uncertainty of _pd_proc.d_spacing.
_pd_proc.diffractogram_id
CIF
Label identifying the diffraction measurement that the data tabulated in the PD_PROC category belong to. This may be omitted in the usual case that only one diffraction measurement is present in a data block.
_pd_proc.energy_detection
CIF
Detection energy in electronvolts selected by the analyser, if not the same as the incident energy (triple-axis or energy-dispersive data). This may be a single value or may vary for each data point (triple-axis and time-of-flight data).
Also known as: _pd_proc_energy_detection
_pd_proc.energy_detection_su
CIF
Standard uncertainty of _pd_proc.energy_detection.
_pd_proc.energy_incident
CIF
Incident energy in electronvolts of the source computed from secondary calibration information (time-of-flight and synchrotron data).
Also known as: _pd_proc_energy_incident
_pd_proc.energy_incident_su
CIF
Standard uncertainty of _pd_proc.energy_incident.
_pd_proc.intensity_bkg_calc
CIF
Inclusion of s.u.'s for these values is strongly recommended.
_pd_proc.intensity_bkg_calc is intended to contain the
background intensity for every data point where the
background function has been fitted or estimated (for example, in
all Rietveld and profile fits).
Also known as: _pd_proc_intensity_bkg_calc
_pd_proc.intensity_bkg_calc_su
CIF
Standard uncertainty of _pd_proc.intensity_bkg_calc.
_pd_proc.intensity_bkg_fix
CIF
Inclusion of s.u.'s for these values is strongly recommended.
If the background is estimated for a limited number of points and the calculated background is then extrapolated from these fixed points, indicate the background values for these points with _pd_proc.intensity_bkg_fix. Use a value of '.' for data points where a fixed background has not been defined. The extrapolated background at every point may be specified using _pd_proc.intensity_bkg_calc.
Background values should be on the same scale as the
_pd_proc.intensity_net values. Thus normalization and
correction factors should be applied before
background subtraction (or should be applied to the
background values equally).
The other normalization factors applied to the data set (for
example, Lp corrections, compensation for variation in
counting time) may be specified in _pd_proc.intensity_norm.
The function should be specified as the one used to divide the
measured intensities.
Also known as: _pd_proc_intensity_bkg_fix
_pd_proc.intensity_bkg_fix_su
CIF
Standard uncertainty of _pd_proc.intensity_bkg_fix.
_pd_proc.intensity_incident
CIF
Inclusion of s.u.'s for these values is strongly recommended.
If the intensities have been corrected for a variation of the incident intensity as a function of a data-collection variable (examples: source fluctuations in synchrotrons, -compensated slits in conventional diffractometers, spectral corrections for white-beam experiments), the correction function should be specified as _pd_proc.intensity_incident. The normalization should be specified in _pd_proc.intensity_incident as a value to be used to divide the measured intensities to obtained the normalized diffractogram. Thus, the _pd_proc.intensity_incident values should increase as the incident flux is increased.
Also known as: _pd_proc_intensity_incident
_pd_proc.intensity_incident_su
CIF
Standard uncertainty of _pd_proc.intensity_incident.
_pd_proc.intensity_net
CIF
Inclusion of s.u.'s for these values is strongly recommended.
Intensity values for the processed diffractogram for
each data point (see _pd_proc.2theta_*, _pd_proc.wavelength
etc.) after background subtraction, normalization, and other
correction factors have been applied (in contrast to
_pd_meas.counts_* or _pd_meas.intensity_* values, which are
uncorrected).
Also known as: _pd_proc_intensity_net
_pd_proc.intensity_net_su
CIF
Standard uncertainty of _pd_proc.intensity_net.
_pd_proc.intensity_norm
CIF
Inclusion of s.u.'s for these values is strongly recommended.
Values in this data item are normalisation-corrected and contain a background component.
Background values (for example, given by _pd_proc.intensity_bkg_calc) should be on the same scale as the _pd_proc.intensity_net values. Thus normalization and correction factors should be applied before background subtraction (or should be applied to the background values equally).
Normalization factors applied to the data set (for
example, Lp corrections, compensation for variation in
counting time) may be specified in _pd_proc.intensity_norm.
The function should be specified as the one used to divide the
measured intensities.
Note that if the intensities have been corrected for a variation
of the incident intensity as a function of a data-collection
variable, the correction function should be specified separately
as _pd_proc.intensity_incident.
Also known as: _pd_proc_intensity_norm
_pd_proc.intensity_norm_su
CIF
Standard uncertainty of _pd_proc.intensity_norm.
_pd_proc.intensity_total
CIF
Inclusion of s.u.'s for these values is strongly recommended.
Intensity values for the processed diffractogram at each data point as a function of angle, time, channel, or some other variable (see _pd_meas.2theta_* etc.), where background, normalization, or other corrections have not been applied.
Also known as: _pd_proc_intensity_total
_pd_proc.intensity_total_su
CIF
Standard uncertainty of _pd_proc.intensity_total.
_pd_proc.ls_weight
CIF
Weight applied to each profile point. These values
may be omitted if the weights are 1/u^2^, where
u is the s.u. for the _pd_proc.intensity_net values.
A weight value of zero is used to indicate a data
point not used for refinement (see
_pd_proc.info_excluded_regions).
Also known as: _pd_proc_ls_weight
_pd_proc.point_id
CIF
Arbitrary label identifying a processed data point. Used to identify a specific entry in a list of processed intensities. The role of this identifier may be adopted by _pd_data.point_id if measured, processed and calculated intensity values are combined in a single list, or by _pd_meas.point_id if measured and processed lists are combined.
Also known as: _pd_proc_point_id
_pd_proc.recip_len_Q
CIF
Length in reciprocal space (|Q|= 2/d) corresponding to an intensity point. Units are inverse angstroms.
Also known as: _pd_proc_recip_len_Q
_pd_proc.recip_len_Q_su
CIF
Standard uncertainty of _pd_proc.recip_len_Q.
_pd_proc.wavelength
CIF
Wavelength in angstroms for the incident radiation as computed from secondary calibration information. This will be most appropriate for measurements where the wavelength varies for each data point and must be looped with the intensity values, such as time-of-flight, or energy-dispersive measurements.
For measurements where the incident radiation can be considered to be monochromatic and has been estimated or refined, for instance, from instrumental parameters or a reference material, please record the wavelength with _diffrn_radiation_wavelength.value and _diffrn_radiation_wavelength.determination.
Also known as: _pd_proc_wavelength
_pd_proc.wavelength_su
CIF
Standard uncertainty of _pd_proc.wavelength.
PD_DIFFRACTOGRAM
CIF
This category includes data names relating to a diffractogram as a whole.
_pd_diffractogram.id
CIF
Arbitrary label identifying a powder diffraction measurement.
If missing, _pd_block.id is used.
_pd_diffractogram.spec_id
CIF
The specimen (see _pd_spec.id) from which the diffractogram was collected.
PD_INSTR
CIF
This section contains information relevant to the instrument used for the diffraction measurement. For most laboratories, very little of this information will change, so a standard file may be prepared and included with each data set.
Note that several definitions in the core CIF dictionary are relevant here. For example, use:
_diffrn_radiation_wavelength.value for the source wavelength, _diffrn_radiation_wavelength.type for the X-ray wavelength type, _diffrn_source.device and _diffrn_source.details for the radiation source, _diffrn_radiation.polarisn_ratio for the source polarization, _diffrn_radiation.probe for the radiation type. For data sets measured with partially monochromatized radiation, for example, where both K~1~ and K~2~ are present, it is important that all wavelengths present are included in a loop_ using _diffrn_radiation_wavelength.value to define the wavelength and _diffrn_radiation_wavelength.wt to define the relative intensity of that wavelength. It is required that _diffrn_radiation_wavelength.id also be present in the wavelength loop. It may also be useful to create a "dummy" ID to use for labelling peaks/reflections where the K~1~ and K~2~ wavelengths are not resolved. Set _diffrn_radiation_wavelength.wt to be 0 for such a dummy ID.
In the PD_INSTR definitions, the term monochromator refers to a primary beam (pre-specimen) monochromator and the term analyser refers to post-diffraction (post-specimen) monochromator. The analyser may be fixed for specific wavelength or may be capable of being scanned.
It is strongly recommended that the core dictionary term _diffrn_radiation.probe (specifying the nature of the radiation used) is employed for all data sets.
_pd_instr.2theta_monochr_pre
CIF
The 2 angle for a pre-specimen monochromator (see also
_pd_instr.monochr_pre_spec).
Also known as: _pd_instr_2theta_monochr_pre
_pd_instr.beam_size_ax
CIF
Axial dimension of the radiation beam at the specimen position (in millimetres). The perpendicular to the plane containing the incident and scattered beam is the axial (*_ax) direction.
Also known as: _pd_instr_beam_size_ax
_pd_instr.beam_size_eq
CIF
Equatorial dimensions of the radiation beam at the specimen position (in millimetres). The equatorial dimension is in the plane of scattering.
Also known as: _pd_instr_beam_size_eq
_pd_instr.cons_illum_flag
CIF
Use 'yes' for instruments where the divergence slit is
-compensated to yield a constant illumination length
(also see _pd_instr.cons_illum_len).
For other flat-plate instruments, where the illumination
length changes with 2, specify 'no'. Note that
if the length is known, it may be specified using
_pd_instr.var_illum_len.
Also known as: _pd_instr_cons_illum_flag
_pd_instr.cons_illum_len
CIF
Use _pd_instr.cons_illum_len for instruments where the length of
specimen illuminated does not vary with 2, usually achieved by
adjustment of the divergence slits (sometimes known as
-compensated slits).
Also known as: _pd_instr_cons_illum_len
_pd_instr.detector_circle_radius
CIF
The radius of the detector circle (also called the 'goniometer circle' or 'diffractometer circle').
The detector circle is defined either by the centre of the active window of a stationary detector, or, in most cases, by a detector moving around the specimen. The radius is the distance from the specimen to the detector.
In this construction, the detector radius is constant for all measurement points. For geometries where this is not the case, see _pd_instr.dist_vsrc_spec and _pd_instr.dist_spec_vdetc.
Where the specimen-detector distance is difficult to define, for example, for a large, flat, area detector, the distance refers to the closest approach of the detector to the specimen.
See the discussion on 'detector circle' or 'goniometer circle' in International Tables Vol H, S2.1.4.1 for further information.
_pd_instr.dist_mono_spec
CIF
Specifies distances in millimetres from the monochromator to the specimen. Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_dist_mono/spec
_pd_instr.dist_src_mono
CIF
Specifies distance in millimetres from the radiation source to the monochromator. Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_dist_src/mono
_pd_instr.dist_src_spec
CIF
Specifies distances in millimetres from the radiation source to the specimen. Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use
Also known as: _pd_instr_dist_src/spec
_pd_instr.divg_ax_mono_spec
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) between the monochromator and the specimen. Values are the maximum divergence angles in degrees, as limited by slits or beamline optics other than Soller slits (see _pd_instr.soller_ax_*). Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_divg_ax_mono/spec
_pd_instr.divg_ax_src_mono
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) between the radiation source and monochromator. Values are the maximum divergence angles in degrees, as limited by slits or beamline optics other than Soller slits (see _pd_instr.soller_ax_*). Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_divg_ax_src/mono
_pd_instr.divg_ax_src_spec
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) between the radiation source and specimen. Values are the maximum divergence angles in degrees, as limited by slits or beamline optics other than Soller slits (see _pd_instr.soller_ax_*). Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use
Also known as: _pd_instr_divg_ax_src/spec
_pd_instr.divg_eq_mono_spec
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) between the monochromator and the specimen Values are the maximum divergence angles in degrees, as limited by slits or beamline optics other than Soller slits (see _pd_instr.soller_eq_*). Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_divg_eq_mono/spec
_pd_instr.divg_eq_src_mono
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) between the radiation source and monochromator. Values are the maximum divergence angles in degrees, as limited by slits or beamline optics other than Soller slits (see _pd_instr.soller_eq_*). Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_divg_eq_src/mono
_pd_instr.divg_eq_src_spec
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) between the radiation source and specimen. Values are the maximum divergence angles in degrees, as limited by slits or beamline optics other than Soller slits (see _pd_instr.soller_eq_*). Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_divg_eq_src/spec
_pd_instr.geometry
CIF
A description of the diffractometer type or geometry.
Also known as: _pd_instr_geometry
Examples:
Bragg-Brentano
Guinier
Parallel-beam non-focusing optics with channel-cut monochromator and linear position-sensitive detector
_pd_instr.id
CIF
Arbitrary label identifying a powder diffraction instrument.
_pd_instr.location
CIF
The name and location of the instrument where measurements were made. This is used primarily to identify data sets measured away from the author's home facility, at shared resources such as a reactor or spallation source.
Also known as: _pd_instr_location
Example:
SEPD diffractometer, IPNS, Argonne National Lab (USA)
_pd_instr.monochr_pre_spec
CIF
Indicates the method used to obtain monochromatic radiation. Use _pd_instr.monochr_pre_spec to describe the primary beam monochromator (pre-specimen monochromation). Use _pd_instr.monochr_post_spec to specify the post-diffraction analyser (post-specimen monochromation).
When a monochromator crystal is used, the material and the indices of the Bragg reflection are specified.
Note that monochromators may have either 'parallel' or 'antiparallel' orientation. It is assumed that the geometry is parallel unless specified otherwise. In a parallel geometry, the position of the monochromator allows the incident beam and the final post-specimen and post-monochromator beam to be as close to parallel as possible. In a parallel geometry, the diffracting planes in the specimen and monochromator will be parallel when 2~monochromator~ is equal to 2~specimen~. For further discussion see R. Jenkins & R. Snyder (1996). Introduction to X-ray Powder Diffraction, pp. 164-165. New York: Wiley.
Also known as: _pd_instr_monochr_pre_spec
Examples:
Zr filter
Ge 220
none
equatorial mounted graphite (0001)
Si (111), antiparallel
_pd_instr.slit_ax_mono_spec
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) for the instrument as a slit width (as opposed to a divergence angle). Values are the width of the slit (in millimetres) defining collimation between the monochromator and the specimen. Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_slit_ax_mono/spec
_pd_instr.slit_ax_src_mono
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) for the instrument as a slit width (as opposed to a divergence angle). Values are the width of the slit (in millimetres) defining collimation between the radiation source and monochromator. Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_slit_ax_src/mono
_pd_instr.slit_ax_src_spec
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) for the instrument as a slit width (as opposed to a divergence angle). Values are the width of the slit (in millimetres) defining collimation between the radiation source and the specimen. Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_slit_ax_src/spec
_pd_instr.slit_eq_mono_spec
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) for the instrument as a slit width (as opposed to a divergence angle). Values are the width of the slit (in millimetres) defining collimation between the monochromator and the specimen. Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_slit_eq_mono/spec
_pd_instr.slit_eq_src_mono
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) for the instrument as a slit width (as opposed to a divergence angle). Values are the width of the slit (in millimetres) defining collimation between the radiation source and monochromator. Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_slit_eq_src/mono
_pd_instr.slit_eq_src_spec
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) for the instrument as a slit width (as opposed to a divergence angle). Values are the width of the slit (in millimetres) defining collimation between the radiation source and the specimen. Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_slit_eq_src/spec
_pd_instr.soller_ax_mono_spec
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) for the instrument. Values are the maximum divergence angles in degrees, as limited by Soller slits located between the monochromator and specimen. Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_soller_ax_mono/spec
_pd_instr.soller_ax_src_mono
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) for the instrument. Values are the maximum divergence angles in degrees, as limited by Soller slits located thus: Collimation between the radiation source and monochromator; Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use, and *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_soller_ax_src/mono
_pd_instr.soller_ax_src_spec
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) for the instrument. Values are the maximum divergence angles in degrees, as limited by Soller slits located between the radiation source and specimen. Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_soller_ax_src/spec
_pd_instr.soller_eq_mono_spec
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) for the instrument. Values are the maximum divergence angles in degrees, as limited by Soller slits located between the monochromator and the specimen. Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_soller_eq_mono/spec
_pd_instr.soller_eq_src_mono
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) for the instrument. Values are the maximum divergence angles in degrees, as limited by Soller slits located thus: Collimation between the radiation source and monochromator; Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use, and *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_soller_eq_src/mono
_pd_instr.soller_eq_src_spec
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) for the instrument. Values are the maximum divergence angles in degrees, as limited by Soller slits located between the radiation source and monochromator. Note that *_src_spec is used in place of *_src_mono and *_mono_spec if there is no monochromator in use.
Also known as: _pd_instr_soller_eq_src/spec
_pd_instr.source_size_ax
CIF
Axial intrinsic dimension of the radiation source (in millimetres). The perpendicular to the plane containing the incident and scattered beam is the axial (*_ax) direction.
Also known as: _pd_instr_source_size_ax
_pd_instr.source_size_eq
CIF
Equatorial intrinsic dimension of the radiation source (in millimetres). The equatorial direction is in the plane containing the incident and scattered beam.
Also known as: _pd_instr_source_size_eq
_pd_instr.special_details
CIF
A brief description of the instrument giving details that cannot be given in other PD_INSTR entries.
Also known as: _pd_instr_special_details
PD_INSTR_DETECTOR
CIF
This section contains information relevant to the detector geometry used for the diffraction measurement. For most laboratories, very little of this information will change, so a standard file may be prepared and included with each data set.
The term analyser refers to post-diffraction (post-specimen) monochromator. The analyser may be fixed for specific wavelength or may be capable of being scanned.
For multiple-detector instruments it may be necessary to loop the
*_anal_detc or *_spec_detc values (for _pd_instr.dist_*,
_pd_instr.divg_*, _pd_instr.slit_* and _pd_instr.soller_*) with
the detector ID's (_pd_instr_detector.id).
_pd_instr.2theta_monochr_post
CIF
The 2 angle for a post-specimen
monochromator (also called an analyser)
(see also _pd_instr.monochr_post_spec).
Also known as: _pd_instr_2theta_monochr_post
_pd_instr.dist_anal_detc
CIF
Specifies the distance in millimetres from the analyser to the detector. Note that *_spec_detc is used in place of *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_dist_anal/detc
_pd_instr.dist_spec_anal
CIF
Specifies distances in millimetres from the specimen to the analyser. Note that *_spec_detc is used in place of *_spec_anal if there is no analyser in use.
Also known as: _pd_instr_dist_spec/anal
_pd_instr.dist_spec_detc
CIF
Specifies distance in millimetres from the specimen to the detector. Note that *_spec_anal and *_anal_detc are used instead of *_spec_detc if there is an analyser in use.
Also known as: _pd_instr_dist_spec/detc
_pd_instr.divg_ax_anal_detc
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) between the analyser and the detector. Values are the maximum divergence angles in degrees, as limited by slits or beamline optics other than Soller slits (see _pd_instr.soller_ax_*). Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_divg_ax_anal/detc
_pd_instr.divg_ax_spec_anal
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) between the specimen and the analyser. Values are the maximum divergence angles in degrees, as limited by slits or beamline optics other than Soller slits (see _pd_instr.soller_ax_*). Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_divg_ax_spec/anal
_pd_instr.divg_ax_spec_detc
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) between the specimen and the detector. Values are the maximum divergence angles in degrees, as limited by slits or beamline optics other than Soller slits (see _pd_instr.soller_ax_*). Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_divg_ax_spec/detc
_pd_instr.divg_eq_anal_detc
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) between the analyser and the detector. Values are the maximum divergence angles in degrees, as limited by slits or beamline optics other than Soller slits (see _pd_instr.soller_eq_*). Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_divg_eq_anal/detc
_pd_instr.divg_eq_spec_anal
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) between the specimen and the analyser. Values are the maximum divergence angles in degrees, as limited by slits or beamline optics other than Soller slits (see _pd_instr.soller_eq_*). Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_divg_eq_spec/anal
_pd_instr.divg_eq_spec_detc
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) between the specimen and the detector. Values are the maximum divergence angles in degrees, as limited by slits or beamline optics other than Soller slits (see _pd_instr.soller_eq_*). Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_divg_eq_spec/detc
_pd_instr.monochr_post_spec
CIF
Indicates the method used to obtain monochromatic radiation. Use _pd_instr.monochr_pre_spec to describe the primary beam monochromator (pre-specimen monochromation). Use _pd_instr.monochr_post_spec to specify the post-diffraction analyser (post-specimen monochromation).
When a monochromator crystal is used, the material and the indices of the Bragg reflection are specified.
Note that monochromators may have either 'parallel' or 'antiparallel' orientation. It is assumed that the geometry is parallel unless specified otherwise. In a parallel geometry, the position of the monochromator allows the incident beam and the final post-specimen and post-monochromator beam to be as close to parallel as possible. In a parallel geometry, the diffracting planes in the specimen and monochromator will be parallel when 2~monochromator~ is equal to 2~specimen~. For further discussion see R. Jenkins & R. Snyder (1996). Introduction to X-ray Powder Diffraction, pp. 164-165. New York: Wiley.
Also known as: _pd_instr_monochr_post_spec
Examples:
Zr filter
Ge 220
none
equatorial mounted graphite (0001)
Si (111), antiparallel
_pd_instr.slit_ax_anal_detc
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) for the instrument as a slit width (as opposed to a divergence angle). Values are the width of the slit (in millimetres) defining collimation between the analyser and the detector. Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_slit_ax_anal/detc
_pd_instr.slit_ax_spec_anal
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) for the instrument as a slit width (as opposed to a divergence angle). Values are the width of the slit (in millimetres) defining collimation between the specimen and the analyser. Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_slit_ax_spec/anal
_pd_instr.slit_ax_spec_detc
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) for the instrument as a slit width (as opposed to a divergence angle). Values are the width of the slit (in millimetres) defining collimation between the specimen and the detector. Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_slit_ax_spec/detc
_pd_instr.slit_eq_anal_detc
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) for the instrument as a slit width (as opposed to a divergence angle). Values are the width of the slit (in millimetres) defining collimation between the analyser and the detector. Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_slit_eq_anal/detc
_pd_instr.slit_eq_spec_anal
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) for the instrument as a slit width (as opposed to a divergence angle). Values are the width of the slit (in millimetres) defining collimation between the specimen and the analyser. Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_slit_eq_spec/anal
_pd_instr.slit_eq_spec_detc
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) for the instrument as a slit width (as opposed to a divergence angle). Values are the width of the slit (in millimetres) defining collimation between the specimen and the detector. Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_slit_eq_spec/detc
_pd_instr.soller_ax_anal_detc
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) for the instrument. Values are the maximum divergence angles in degrees, as limited by Soller slits located between the analyser and the detector. Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_soller_ax_anal/detc
_pd_instr.soller_ax_spec_anal
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) for the instrument. Values are the maximum divergence angles in degrees, as limited by Soller slits located between the specimen and the analyser. Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_soller_ax_spec/anal
_pd_instr.soller_ax_spec_detc
CIF
Describes collimation in the axial direction (perpendicular to the plane containing the incident and diffracted beams) for the instrument. Values are the maximum divergence angles in degrees, as limited by Soller slits located between the specimen and the detector. Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_soller_ax_spec/detc
_pd_instr.soller_eq_anal_detc
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) for the instrument. Values are the maximum divergence angles in degrees, as limited by Soller slits located between the analyser and the detector. Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_soller_eq_anal/detc
_pd_instr.soller_eq_spec_anal
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) for the instrument. Values are the maximum divergence angles in degrees, as limited by Soller slits located between the specimen and the analyser. Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_soller_eq_spec/anal
_pd_instr.soller_eq_spec_detc
CIF
Describes collimation in the equatorial plane (the plane containing the incident and diffracted beams) for the instrument. Values are the maximum divergence angles in degrees, as limited by Soller slits located between the specimen and the detector in use. Note that *_spec_detc is used in place of *_spec_anal and *_anal_detc if there is no analyser in use.
Also known as: _pd_instr_soller_eq_spec/detc
_pd_instr_detector.id
CIF
A code which identifies the detector or channel number in a
position-sensitive, energy-dispersive or other multiple-detector
instrument for which individual instrument geometry is being
defined. Note that this code should match the code name used for
_pd_meas.detector_id. Where a single detector is used, this
may be omitted.
PD_MEAS_INFO_AUTHOR
CIF
This section contains information about the person(s) who conducted the measurement.
_pd_meas_info_author.address
CIF
The address of the person who measured the data set. If there
is more than one person, this will be looped with
_pd_meas_info_author.name.
Also known as: _pd_meas_info_author_address
_pd_meas_info_author.diffractogram_id
CIF
The diffractogram (see _pd_diffractogram.id) to which the author details
relate.
_pd_meas_info_author.email
CIF
The e-mail address of the person who measured the data set. If
there is more than one person, this will be looped with
_pd_meas_info_author.name.
Also known as: _pd_meas_info_author_email
_pd_meas_info_author.fax
CIF
The fax number of the person who measured the data set. If
there is more than one person, this will be looped with
_pd_meas_info_author.name. The recommended style is
the international dialing prefix, followed by the area code in
parentheses, followed by the local number with no spaces.
Also known as: _pd_meas_info_author_fax
_pd_meas_info_author.name
CIF
The name of the person who measured the data set. The family name(s), followed by a comma and including any dynastic components, precedes the first name(s) or initial(s). For more than one person use a loop to specify multiple values.
Also known as: _pd_meas_info_author_name
_pd_meas_info_author.phone
CIF
The telephone number of the person who measured the data set.
If there is more than one person, this will be looped with
_pd_meas_info_author.name. The recommended style is
the international dialing prefix, followed by the area code in
parentheses, followed by the local number with no spaces.
Also known as: _pd_meas_info_author_phone
PD_MEAS_OVERALL
CIF
This section contains information about the conditions used for
the measurement of the diffraction data set, prior to processing
and application of correction terms. While additional
information may be added to the CIF as data are processed and
transported between laboratories (possibly with the addition of
a new _pd_block.id entry), the information in this section of
the CIF will rarely be changed once data collection is complete.
_pd_meas.2theta_fixed
CIF
The 2 diffraction angle in degrees for measurements
in a white-beam fixed-angle experiment. For measurements
where 2 is scanned, see _pd_meas.2theta_scan or
_pd_meas.2theta_range_*.
Also known as: _pd_meas_2theta_fixed
_pd_meas.2theta_fixed_su
CIF
Standard uncertainty of _pd_meas.2theta_fixed.
_pd_meas.2theta_range_inc
CIF
2 diffraction angle increment in degrees used for the
measurement of intensities. These may be used in place of the
_pd_meas.2theta_scan values for data sets measured with a
constant step size.
Also known as: _pd_meas_2theta_range_inc
_pd_meas.2theta_range_max
CIF
Maximum 2 diffraction angle in degrees used for the
measurement of intensities. These may be used in place of the
_pd_meas.2theta_scan values for data sets measured with a
constant step size.
Also known as: _pd_meas_2theta_range_max
_pd_meas.2theta_range_min
CIF
Minimum 2 diffraction angle in degrees used for the
measurement of intensities. These may be used in place of the
_pd_meas.2theta_scan values for data sets measured with a
constant step size.
Also known as: _pd_meas_2theta_range_min
_pd_meas.angle_chi
CIF
The diffractometer angle in degrees for an instrument with a Euler circle. The definitions for these angles follow the convention of International Tables for X-ray Crystallography (1974), Vol. IV, p. 276.
Also known as: _pd_meas_angle_chi
_pd_meas.angle_chi_su
CIF
Standard uncertainty of _pd_meas.angle_chi.
_pd_meas.angle_omega
CIF
The diffractometer angle in degrees for an instrument with a Euler circle. The definitions for these angles follow the convention of International Tables for X-ray Crystallography (1974), Vol. IV, p. 276.
Also known as: _pd_meas_angle_omega
_pd_meas.angle_omega_su
CIF
Standard uncertainty of _pd_meas.angle_omega.
_pd_meas.angle_phi
CIF
The diffractometer angle in degrees for an instrument with a Euler circle. The definitions for these angles follow the convention of International Tables for X-ray Crystallography (1974), Vol. IV, p. 276.
Also known as: _pd_meas_angle_phi
_pd_meas.angle_phi_su
CIF
Standard uncertainty of _pd_meas.angle_phi.
_pd_meas.datetime_initiated
CIF
The date and time of the data-set measurement. Entries should follow the standard RFC 3339 ABNF format 'yyyy-mm-ddThh:mm:ss{Z|[+-]zz:zz}'. Where possible, give the time when the measurement was started, rather than when it was completed.
Also known as: _pd_meas_datetime_initiated
Examples:
1990-07-13T14:40:00Z
2042-12-13T02:37:23Z
2005-03-03T12:02:09.17+09:30
2015-10-30T22:45:00-02:00
1912-02-03T11:47:00Z
1979-09-01T12:00:00Z
_pd_meas.number_of_points
CIF
Total number of points in the measured diffractogram.
Also known as: _pd_meas_number_of_points
_pd_meas.rocking_angle
CIF
The angular range in degrees through which a specimen
is rotated or oscillated during a measurement step
(see _pd_meas.rocking_axis).
Also known as: _pd_meas_rocking_angle
_pd_meas.rocking_angle_su
CIF
Standard uncertainty of _pd_meas.rocking_angle.
_pd_meas.rocking_axis
CIF
The axis (or axes) used to rotate or rock the
specimen for better randomization of crystallites
(see _pd_meas.rocking_angle).
Also known as: _pd_meas_rocking_axis
_pd_meas.scan_method
CIF
Code identifying the method for scanning reciprocal space. The designation `fixed' should be used for measurements where film, a stationary position-sensitive or area detector or other non-moving detection mechanism is used to measure diffraction intensities.
Also known as: _pd_meas_scan_method
_pd_meas.special_details
CIF
Special details of the diffraction measurement process. Include information about source instability, degradation etc. However, this item should not be used to record information that can be specified in other PD_MEAS entries.
Also known as: _pd_meas_special_details
_pd_meas.units_of_intensity
CIF
Units for intensity measurements when _pd_meas.intensity_*
is used. Note that use of 'counts' or 'counts per second'
here is strongly discouraged: convert the intensity
measurements to counts and use _pd_meas.counts_* and
_pd_meas.step_count_time instead of _pd_meas.intensity_*.
Also known as: _pd_meas_units_of_intensity
Examples:
estimated from strip chart
arbitrary, from film density
counts, with automatic dead-time correction applied
_pd_meas_overall.diffractogram_id
CIF
The diffractogram (see _pd_diffractogram.id) to which the measurement
conditions relate.
PD_PEAK
CIF
This section contains peak information extracted from the
measured or, if present, the processed diffractogram. Each
peak in this table will have a unique label (see _pd_peak.id).
The reflections and phases associated with each peak will be
specified in other sections (see REFLN and PD_PHASE).
Note that peak positions are customarily determined from the processed diffractogram and thus corrections for position and intensity will have been previously applied.
_pd_peak.2theta_centroid
CIF
Position of the centroid of a peak as a 2 angle.
Also known as: _pd_peak_2theta_centroid
_pd_peak.2theta_centroid_su
CIF
Standard uncertainty of _pd_peak.2theta_centroid.
_pd_peak.2theta_maximum
CIF
Position of the maximum of a peak as a 2 angle.
Also known as: _pd_peak_2theta_maximum
_pd_peak.2theta_maximum_su
CIF
Standard uncertainty of _pd_peak.2theta_maximum.
_pd_peak.d_spacing
CIF
Peak position as a d-spacing in angstroms.
Also known as: _pd_peak_d_spacing
_pd_peak.d_spacing_su
CIF
Standard uncertainty of _pd_peak.d_spacing.
_pd_peak.id
CIF
An arbitrary code is assigned to each peak. Used to link with
_pd_refln.peak_id so that multiple hkl and/or phase
identifications can be assigned to a single peak.
Each peak will have a unique code. In cases
where two peaks are severely overlapped, it may be
desirable to list them as a single peak.
A peak ID must be included for every peak.
Also known as: _pd_peak_id
_pd_peak.intensity
CIF
Integrated area for the peak, with the same scaling as the _pd_proc.intensity_* values. It is good practice to include s.u.'s for these values.
Also known as: _pd_peak_intensity
_pd_peak.intensity_su
CIF
Standard uncertainty of _pd_peak.intensity.
_pd_peak.pk_height
CIF
The maximum intensity of the peak, either extrapolated or the highest observed intensity value. The same scaling is used for the _pd_proc.intensity_* values. It is good practice to include s.u.'s for these values.
Also known as: _pd_peak_pk_height
_pd_peak.pk_height_su
CIF
Standard uncertainty of _pd_peak.pk_height.
_pd_peak.wavelength_id
CIF
Code identifying the wavelength appropriate for this peak
from the wavelengths in the _diffrn_radiation_ list.
(See _diffrn_radiation_wavelength.id.) Most commonly used
to distinguish K~1~ peaks from K~2~ or to designate
where K~1~ and K~2~ peaks cannot be resolved. For
complex peak tables with multiple superimposed peaks,
specify wavelengths in the reflection table using
_refln.wavelength_id rather than identifying peaks by
wavelength.
Also known as: _pd_peak_wavelength_id
_pd_peak.width_2theta
CIF
Peak width as full-width at half-maximum expressed as a 2 value in degrees.
Also known as: _pd_peak_width_2theta
_pd_peak.width_2theta_su
CIF
Standard uncertainty of _pd_peak.width_2theta.
_pd_peak.width_d_spacing
CIF
Peak width as full-width at half-maximum expressed as a d-spacing in angstroms.
Also known as: _pd_peak_width_d_spacing
_pd_peak.width_d_spacing_su
CIF
Standard uncertainty of _pd_peak.width_d_spacing.
PD_PEAK_OVERALL
CIF
This category describes general aspects of the peak extraction process.
_pd_peak.special_details
CIF
Detailed description of any non-routine processing steps used for peak determination or other comments related to the peak table that cannot be given elsewhere.
Also known as: _pd_peak_special_details
PD_PHASE
CIF
This section contains a description of the phases contributing to the powder diffraction data set. Note that if multiple-phase Rietveld or other structural analysis is performed, the structural results will be placed in different data blocks, using CIF entries from the core CIF dictionary.
The _pd_phase_block.id or _pd_phase.id entry points to the CIF block with structural parameters for each crystalline phase.
_pd_phase.id
CIF
Arbitrary label uniquely identifying a phase.
_pd_phase.name
CIF
The name of the phase. It may be designated as unknown, or by a mineral name, structure type, chemical formula, or other identifier.
Also known as: _pd_phase_name
Examples:
NIST 640e Silicon standard
Al2O3
malachite
Calcium sulphate hemihydrate. ACME Chemicals, batch #12090.
Olivine#Mg2SiO4
PD_PHASE_BLOCK
CIF
A table of phases relevant to the current data
block. Each phase is identified by the block identifier
of the data block containing the phase information,
and the _pd_phase.id of the phase contained within
that block.
_pd_phase_block.id
CIF
A block ID code identifying a block containing phase information.
Also known as: _pd_phase_block_id
_pd_phase_block.phase_id
CIF
A phase id code (see _pd_phase.id) that identifies the phase contained in the data block pointed to by _pd_phase_block.id
Also known as: _pd_phase_id
PD_PHASE_MASS
CIF
This category describes the percent composition by mass of phases in a specimen. Values are derived from modelling a particular diffraction measurement on a specimen and should not be used where the mass composition has been determined by other means.
Examples:
_audit.schema Custom
loop_ _pd_phase_mass.diffractogram_id _pd_phase_mass.phase_id _pd_phase_mass.percent _pd_phase_mass.percent_su A_DIFFRACTOGRAM PHASE_1 45.45 0.42 A_DIFFRACTOGRAM PHASE_2 37.42 0.63 A_DIFFRACTOGRAM PHASE_3 17.13 0.53
_audit.schema Custom
loop_ _pd_phase_mass.phase_id _pd_phase_mass.percent _pd_phase_mass.percent_su PHASE_1 45.45 0.42 PHASE_2 37.42 0.63 PHASE_3 17.13 0.53
_pd_phase_mass.diffractogram_id
CIF
A diffractogram id to which the phase mass percent value relates.
_pd_phase_mass.percent
CIF
Total mass of the phase expressed as a percentage of the total mass of the specimen.
If _pd_qpa_internal_std.mass_percent or _pd_qpa_external_std.k_factor is present, the values given are assumed to be in absolute terms.
The value of the mass percent given to the internal standard
represents the total crystalline contribution of that standard.
That is, if 1 g of a 90% crystalline internal standard is added
to 3 g of sample, the value of _pd_phase_mass.percent for the
standard is 22.5%.
Also known as: _pd_phase_mass_%
_pd_phase_mass.percent_su
CIF
Standard uncertainty of _pd_phase_mass.percent.
_pd_phase_mass.phase_id
CIF
The phase (see _pd_phase.id) to which the percent mass relates.
PD_PREF_ORIENT
CIF
This section contains a description of preferred-orientation corrections applied to a phase when modelling its contribution to a histogram.
March-Dollase and spherical harmonics corrections can be given explicitly.
For other methods, use the _pd_pref_orient.special_details.
See Dollase, W. A. (1986). J. Appl. Cryst. 19, 267-272 and Jarvinen, M. (1993). J. Appl. Cryst. 26, 525-531 for further information.
_pd_pref_orient.diffractogram_id
CIF
The diffractogram (see _pd_diffractogram.id) to which the preferred-
orientation correction relates.
_pd_pref_orient.phase_id
CIF
The phase (see _pd_phase.id) to which the preferred-orientation
correction relates.
_pd_pref_orient.special_details
CIF
Description of the preferred-orientation correction if such a correction is used, and it cannot be described as a March-Dollase