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_PD_BLOCK_[PD]
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_calib_std_external_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 ID's 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 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 are in the standard CIF format 'yyyy-mm-ddThh:mm:ss+zz' Use of seconds and a time zone is optional, but use of hours and minutes is strongly encouraged as this will help ensure that the ID code is unique.
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.
Examples:
1991-15-09T16:54|Si-std|B.Toby|D500#1234-987
1991-15-09T16:54|SEPD7234|B.Toby|SEPD.IPNS.ANL.GOV
_PD_CALC_[PD]
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_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, the atom coordinates and other crystallographic information should be included using the core CIF _atom_site_ and _cell_ data items.
_PD_CALIB_[PD]
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. The _pd_calibration_ items, however, are never looped.
Examples:
_pd_calib_std_external_block_id QuartzPlate|D500#1234-987|B.Toby|91-15-09|14:02 _pd_calib_std_external_name 'Arkansas Stone quartz plate'
_pd_calibration_conversion_eqn
; 2~actual~ = 2~setting~ + arctan(
cos(P~1~)/{1/[P~0~ (CC - CH~0~ - P~2~ CC^2^)] - sin(P~1~)})
;
_pd_calib_2theta
CIF
Data names: _pd_calib_2theta_offset _pd_calib_2theta_off_point _pd_calib_2theta_off_min _pd_calib_2theta_off_max
_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~
For cases where the _pd_calib_2theta_offset value is not a constant, but rather varies with 2, a set of offset values can be 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_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_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.
_pd_calib_std_external
CIF
Data names: _pd_calib_std_external_block_id _pd_calib_std_external_name
Identifies the data set used as an external standard for
the diffraction angle or the intensity calibrations.
*_name specifies the name of the material and
*_id the _pd_block_id for the CIF containing calibration
measurements. If more than one data set is used for
calibration, these fields may be looped.
_pd_calib_std_internal_mass_%
CIF
Per cent presence of the internal standard specified by the
data item _pd_calib_std_internal_name expressed as 100 times
the ratio of the amount of standard added to the original
sample mass.
_pd_calib_std_internal_name
CIF
Identity of material(s) used as an internal intensity standard.
Examples:
NIST 640a Silicon standard
Al2O3
_PD_CHAR_[PD]
CIF
This section contains experimental (non-diffraction) information
relevant to the chemical and physical nature of the material.
_pd_char_atten_coef_mu
CIF
Data names: _pd_char_atten_coef_mu_obs _pd_char_atten_coef_mu_calc
The observed and calculated linear attenuation coefficient,
, in units of inverse millimetres. Note that this quantity is sometimes referred to as the mass absorption coefficient; however, this term accounts for other potentially significant losses of incident radiation, for example incoherent scattering of neutrons.
The calculated will be obtained from the atomic content of
the cell, the average density (allowing for specimen packing)
and the radiation wavelength. The observed will be
determined by a transmission measurement.
Note that _pd_char_atten_coef_mu_calc will differ from
_exptl_absorpt_coefficient_mu if the packing density is
not unity.
_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.
Examples:
dark_green
orange_red
brownish_red
yellow_metallic
_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.).
_pd_char_special_details
CIF
Additional characterization information relevant to the sample
or documentation of non-routine processing steps used for characterization.
_PD_DATA_[PD]
CIF
The PD_DATA category contains raw, processed and calculated
data points in a diffraction data set. In many cases, it is convenient to tabulate calculated values against the raw and processed measurements, and so the various _pd_meas_, _pd_proc_ and _pd_calc_ data items belonging to this category may be looped together. In some instances, however, it makes more sense to maintain separate tables of the data contributing to the measured and processed diffractograms (for example, a profile may be calculated at 2theta values different from those of the measured data points). To facilitate the identification of equivalent points in these separate tables, separate identifiers are defined.
Examples:
loop_ _pd_data_point_id _pd_meas_intensity_total _pd_proc_ls_weight _pd_proc_intensity_bkg_calc _pd_calc_intensity_total 1 240(15) 0.00417 214.5 214.5 2 219(15) 0.00457 214.3 214.2 3 206(14) 0.00485 214.0 214.0 4 212(15) 0.00472 213.8 213.7 5 190(14) 0.00526 213.5 213.5 6 203(14) 0.00493 213.2 213.2 # - - - - data truncated for brevity - - - -
loop_ _pd_meas_point_id _pd_meas_intensity_total 1 240(15) 2 219(15) 3 206(14) 4 212(15) 5 190(14) 6 203(14)
loop_ _pd_proc_point_id _pd_proc_ls_weight _pd_proc_intensity_bkg_calc 1 0.00417 214.5 2 0.00457 214.3 3 0.00485 214.0 4 0.00472 213.8 5 0.00526 213.5 6 0.00493 213.2
loop_ _pd_calc_point_id _pd_calc_intensity_total 1 214.5 2 214.2 3 214.0 4 213.7 5 213.5 6 213.2
loop_ _pd_meas_point_id _pd_meas_2theta_scan _pd_meas_intensity_total 1 21.0 24 2 21.2 32 3 21.4 67 4 21.6 98
loop_ _pd_calc_point_id _pd_proc_2theta_corrected _pd_calc_intensity_total 1 21.0 26 1a 21.3 56 4 21.6 76 4a 21.9 90
_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_angle
CIF
Data names: _pd_meas_angle_chi _pd_meas_angle_omega _pd_meas_angle_phi _pd_meas_angle_2theta
The diffractometer angles 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.
_pd_meas_counts
CIF
Data names: _pd_meas_counts_total _pd_meas_counts_background _pd_meas_counts_container _pd_meas_counts_monitor
Counts measured at the measurement point as a function of
angle, time, channel or some other variable (see _pd_meas_2theta_ etc.).
The defined fields are: _pd_meas_counts_total, scattering from the specimen (with background, specimen mounting or container scattering included); _pd_meas_counts_background, scattering measured without a specimen, specimen mounting etc., often referred to as the instrument background; _pd_meas_counts_container, the specimen container or mounting without a specimen, includes background; _pd_meas_counts_monitor, counts 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.
_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.
_pd_meas_intensity
CIF
Data names: _pd_meas_intensity_total _pd_meas_intensity_background _pd_meas_intensity_container _pd_meas_intensity_monitor
Intensity measurements at the measurement point (see
the definition of _pd_meas_2theta_).
The defined fields are: _pd_meas_intensity_total, scattering from the specimen (with background, specimen mounting or container scattering included); _pd_meas_intensity_background, scattering measured without a specimen, specimen mounting etc., often referred to as the instrument background; _pd_meas_intensity_container, the specimen container or mounting without a specimen, includes background; _pd_meas_intensity_monitor, intensity measured by an incident-beam monitor to calibrate the flux on the specimen.
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.
_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 the _pd_calib_ values.
Do not confuse this with the instrument geometry descriptions given by _pd_instr_dist_.
_pd_meas_rocking_angle
CIF
The angular range in degrees through which a sample is rotated
or oscillated during a measurement step
(see _pd_meas_rocking_axis).
_pd_meas_step_count_time
CIF
The count time in seconds for each intensity measurement.
If this value varies for different intensity measurements, then this item will be placed in the loop with the diffraction measurements. If a single fixed value is used, it may be recorded outside the loop.
_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.
_pd_instr_beam_size
CIF
Data names: _pd_instr_beam_size_ax _pd_instr_beam_size_eq
Axial and equatorial dimensions 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.
_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_).
See _pd_instr_cons_illum_len for instruments where
the divergence slit is -compensated to yield a
constant illumination length.
_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.
_pd_proc_d_spacing
CIF
d-spacing corresponding to an intensity point
from Bragg's law, d = /(2 sin), in units of angstroms.
_pd_proc_energy
CIF
Data names: _pd_proc_energy_incident _pd_proc_energy_detection
Incident energy in electronvolts of the source computed
from secondary calibration information (time-of-flight and synchrotron data). 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).
_pd_proc_intensity
CIF
Data names: _pd_proc_intensity_net _pd_proc_intensity_total _pd_proc_intensity_bkg_calc _pd_proc_intensity_bkg_fix _pd_proc_intensity_incident _pd_proc_intensity_norm
_pd_proc_intensity_net contains intensity values for the
processed diffractogram for each data point (see
_pd_proc_2theta_, _pd_proc_wavelength etc.) after
correction and normalization factors have been applied
(in contrast to _pd_meas_counts_ values, which are
uncorrected).
_pd_proc_intensity_total contains intensity values for the
processed diffractogram for each data point where
background, normalization and other corrections have not
been applied.
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).
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).
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.
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.
_pd_proc_recip_len_Q
CIF
Length in reciprocal space (|Q|= 2/d) corresponding to
an intensity point. Units are inverse angstroms.
_pd_proc_wavelength
CIF
Wavelength in angstroms for the incident radiation as
computed from secondary calibration information. This will be most appropriate for time-of-flight and synchrotron measurements. This will be a single value for continuous-wavelength methods or may vary for each data point and be looped with the intensity values for energy-dispersive measurements.
_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).
_pd_calc_intensity
CIF
Data names: _pd_calc_intensity_net _pd_calc_intensity_total
Intensity values for a computed diffractogram at
each angle setting. 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.
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_.
_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
calculated intensity values are combined in a single list.
_pd_data_point_id
CIF
Arbitrary label identifying an entry in the table of
diffractogram intensity values.
_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 calculated
intensity values are combined in a single list.
_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.
_PD_INSTR_[PD]
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 for the source wavelength, _diffrn_radiation_type for the X-ray wavelength type, _diffrn_source 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 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.
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_calib_detector_id).
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.
Example:
_pd_instr_slit_eq_src/spec 1. _pd_instr_slit_eq_anal/detc 0.2
_pd_instr_geometry Bragg-Brentano _pd_instr_monochr_post_spec 'graphite (0001)' _pd_instr_cons_illum_flag no
_pd_instr_2theta_monochr
CIF
Data names: _pd_instr_2theta_monochr_pre _pd_instr_2theta_monochr_post
The 2 angle for a pre-specimen or post-specimen
monochromator (see _pd_instr_monochr_pre_spec and _pd_instr_monochr_post_spec).
_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.
_pd_instr_cons_illum_len
CIF
Length of the specimen that is illuminated by the radiation
source (in millimetres).
Use _pd_instr_cons_illum_len for instruments where the illumination length does not vary with 2, by adjustment of the divergence slits (sometimes known as -compensated slits). Use _pd_instr_var_illum_len for instruments where the illuminated length of the specimen has been characterized as a function of 2, most commonly true with a fixed divergence slit.
_pd_instr_dist
CIF
Data names: _pd_instr_dist_src/mono _pd_instr_dist_mono/spec _pd_instr_dist_src/spec _pd_instr_dist_spec/anal _pd_instr_dist_anal/detc _pd_instr_dist_spec/detc
Specifies distances in millimetres for the instrument geometry:
*_src/mono, the distance from the radiation source to the monochromator; *_mono/spec, the distance from the monochromator to the specimen; *_src/spec, the distance from the radiation source to the specimen; *_spec/anal, the distance from the specimen to the analyser; *_anal/detc, the distance from the analyser to the detector; *_spec/detc, the distance from the specimen to the detector.
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.
_pd_instr_divg_ax
CIF
Data names: _pd_instr_divg_ax_src/mono _pd_instr_divg_ax_mono/spec _pd_instr_divg_ax_src/spec _pd_instr_divg_ax_spec/anal _pd_instr_divg_ax_anal/detc _pd_instr_divg_ax_spec/detc
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 slits or beamline optics other than Soller slits (see _pd_instr_soller_ax_): *_src/mono, collimation between the radiation source and the monochromator; *_mono/spec, collimation between the monochromator and the specimen; *_src/spec, collimation between the radiation source and the specimen; *_spec/anal, collimation between the specimen and the analyser; *_anal/detc, collimation between the analyser and the detector; *_spec/detc, collimation between the specimen and the detector.
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.
_pd_instr_divg_eq
CIF
Data names: _pd_instr_divg_eq_src/mono _pd_instr_divg_eq_mono/spec _pd_instr_divg_eq_src/spec _pd_instr_divg_eq_spec/anal _pd_instr_divg_eq_anal/detc _pd_instr_divg_eq_spec/detc
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 slits or beamline optics other than Soller slits (see _pd_instr_soller_eq_): *_src/mono, collimation between the radiation source and the monochromator; *_mono/spec, collimation between the monochromator and the specimen; *_src/spec, collimation between the radiation source and the specimen; *_spec/anal, collimation between the specimen and the analyser; *_anal/detc, collimation between the analyser and the detector; *_spec/detc, collimation between the specimen and the detector.
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.
_pd_instr_geometry
CIF
A description of the diffractometer type or geometry.
Examples:
Bragg-Brentano
Guinier
Parallel-beam non-focusing optics with channel-cut monochromator and linear position-sensitive detector
_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.
Example:
SEPD diffractometer, IPNS, Argonne National Lab (USA)
_pd_instr_monochr
CIF
Data names: _pd_instr_monochr_pre_spec _pd_instr_monochr_post_spec
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.
Examples:
Zr filter
Ge 220
none
equatorial mounted graphite (0001)
Si (111), antiparallel
_pd_instr_slit_ax
CIF
Data names: _pd_instr_slit_ax_src/mono _pd_instr_slit_ax_mono/spec _pd_instr_slit_ax_src/spec _pd_instr_slit_ax_spec/anal _pd_instr_slit_ax_anal/detc _pd_instr_slit_ax_spec/detc
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: *_src/mono, collimation between the radiation source and the monochromator; *_mono/spec, collimation between the monochromator and the specimen; *_src/spec, collimation between the radiation source and the specimen; *_spec/anal, collimation between the specimen and the analyser; *_anal/detc, collimation between the analyser and the detector; *_spec/detc, collimation between the specimen and the detector.
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.
_pd_instr_slit_eq
CIF
Data names: _pd_instr_slit_eq_src/mono _pd_instr_slit_eq_mono/spec _pd_instr_slit_eq_src/spec _pd_instr_slit_eq_spec/anal _pd_instr_slit_eq_anal/detc _pd_instr_slit_eq_spec/detc
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: *_src/mono, collimation between the radiation source and the monochromator; *_mono/spec, collimation between the monochromator and the specimen; *_src/spec, collimation between the radiation source and the specimen; *_spec/anal, collimation between the specimen and the analyser; *_anal/detc, collimation between the analyser and the detector; *_spec/detc, collimation between the specimen and the detector.
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.
_pd_instr_soller_ax
CIF
Data names: _pd_instr_soller_ax_src/mono _pd_instr_soller_ax_mono/spec _pd_instr_soller_ax_src/spec _pd_instr_soller_ax_spec/anal _pd_instr_soller_ax_anal/detc _pd_instr_soller_ax_spec/detc
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: *_src/mono, collimation between the radiation source and the monochromator; *_mono/spec, collimation between the monochromator and the specimen; *_src/spec, collimation between the radiation source and the specimen; *_spec/anal, collimation between the specimen and the analyser; *_anal/detc, collimation between the analyser and the detector; *_spec/detc, collimation between the specimen and the detector.
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.
_pd_instr_soller_eq
CIF
Data names: _pd_instr_soller_eq_src/mono _pd_instr_soller_eq_mono/spec _pd_instr_soller_eq_src/spec _pd_instr_soller_eq_spec/anal _pd_instr_soller_eq_anal/detc _pd_instr_soller_eq_spec/detc
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: *_src/mono, collimation between the radiation source and the monochromator; *_mono/spec, collimation between the monochromator and the specimen; *_src/spec, collimation between the radiation source and the specimen; *_spec/anal, collimation between the specimen and the analyser; *_anal/detc, collimation between the analyser and the detector; *_spec/detc, collimation between the specimen and the detector.
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.
_pd_instr_source_size
CIF
Data names: _pd_instr_source_size_ax _pd_instr_source_size_eq
Axial and equatorial intrinsic dimensions
of the radiation source (in millimetres). The perpendicular to the plane containing the incident and scattered beam is the axial (*_ax) direction.
_pd_instr_special_details
CIF
A brief description of the instrument giving
details that cannot be given in other _pd_instr_ entries.
_PD_MEAS_[PD]
CIF
This section contains the measured diffractogram and 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.
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_.
Example:
_pd_meas_info_author_name 'Cranswick, Lachlan' _pd_meas_info_author_email lachlan@dmp.csiro.au _pd_meas_info_author_address ? _pd_meas_datetime_initiated 1992-03-23T17:20
_pd_meas_scan_method step _pd_meas_2theta_range_min 6.0 _pd_meas_2theta_range_max 164.0 _pd_meas_2theta_range_inc 0.025 _pd_meas_step_count_time 2.0
_PD_PEAK_[PD]
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 the _pd_refln_ and
_pd_phase_ sections).
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
CIF
Data names: _pd_peak_2theta_centroid _pd_peak_2theta_maximum
Position of the centroid and maximum of a peak as a
2 angle in degrees.
_pd_peak_d_spacing
CIF
Peak position as a d-spacing in angstroms.
_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.
_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.
_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.
_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
_pd_refln_wavelength_id rather than identifying peaks by
wavelength.
_pd_peak_width_2theta
CIF
Peak width as full-width at half-maximum expressed as
a 2 value in degrees.
_pd_peak_width_d_spacing
CIF
Peak width as full-width at half-maximum expressed as
a d-spacing in angstroms.
_PD_PHASE_[PD]
CIF
This section contains a description of the crystalline 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 entry points to the CIF block with structural parameters for each crystalline phase. The _pd_phase_id serves to link to _pd_refln_phase_id, which is used to label peaks by phase.
_pd_phase_block_id
CIF
A block ID code identifying the phase contributing to
the diffraction peak. 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.
_pd_phase_id
CIF
A code for each crystal phase used to link with
_pd_refln_phase_id.
_pd_phase_mass_%
CIF
Per cent composition of the specified crystal phase
expressed as the total mass of the component with respect to the total mass of the specimen.
_pd_phase_name
CIF
The name of the crystal phase identified by _pd_phase_id.
It may be designated as unknown or by a structure type etc.
_PD_PREP_[PD]
CIF
This section contains descriptive information about how the
sample was prepared.
_pd_prep_conditions
CIF
A description of how the material was prepared
(reaction conditions etc.)
_pd_prep_cool_rate
CIF
Cooling rate in kelvins per minute for samples prepared
at high temperatures. If the cooling rate is not linear
or is unknown (e.g. quenched samples), it should be
described in _pd_prep_conditions instead.
_pd_prep_pressure
CIF
Preparation pressure of the sample in kilopascals. This
is particularly important for materials which are metastable at the measurement pressure, _diffrn_ambient_pressure.
_pd_prep_temperature
CIF
Preparation temperature of the sample in kelvins. This is
particularly important for materials which are metastable at the measurement temperature, _diffrn_ambient_temperature.
_PD_PROC_[PD]
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_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.
_PD_PROC_LS_[PD]
CIF
This section is used to define parameters relevant to a
least-squares fit to a powder diffractogram, using a Rietveld or other full-profile (e.g. Pawley or Le Bail methods) fit.
Note that values in this section refer to full-pattern fitting. Use the appropriate items for single-crystal analyses from the core CIF dictionary for structure refinements using diffraction intensities estimated from a powder diffractogram by pattern-decomposition methods. Also note that many entries in the core _refine_ls_ entries may also be useful (for example _refine_ls_shift/su_*).
_pd_proc_ls_background_function
CIF
Description of the background treatment mechanism used to
fit the data set.
For refinements where the background is computed as a
function that is fitted to minimize the difference between
the observed and calculated patterns, it is
recommended that in addition to a description of the
function (e.g. Chebychev polynomial), the actual equation(s)
used are included in TeX, or a programming language such
as Fortran or C. Include also the values used for the
coefficients used in the background function with their
s.u.'s. The background values for each data point
computed from the function should be specified in
_pd_proc_intensity_bkg_calc.
If background correction is performed using extrapolation from a set of points at fixed locations, these points should be defined using _pd_proc_intensity_bkg_fix, and _pd_proc_ls_background_function should indicate the extrapolation method (linear extrapolation, spline etc.). _pd_proc_ls_background_function should also indicate how the points were determined (automatically, by visual estimation etc.) and whether the values were refined to improve the agreement. The extrapolated background intensity value for each data point should be specified in _pd_proc_intensity_bkg_calc.
_pd_proc_ls_peak_cutoff
CIF
Describes where peak-intensity computation is
discontinued as a fraction of the intensity of the peak at maximum. Thus for a value of 0.005, the tails of a diffraction peak are neglected after the intensity has dropped below 0.5% of the diffraction intensity at the maximum.
_pd_proc_ls_pref_orient_corr
CIF
Description of the preferred-orientation correction if
such a correction is used. Omitting this entry implies that no preferred-orientation correction has been used. If a function form is used, it is recommended that the actual equation in TeX, or a programming language, is used to specify the function as well as a giving a description. Include the value(s) used for the correction with s.u.'s.
_pd_proc_ls_prof
CIF
Data names: _pd_proc_ls_prof_R_factor _pd_proc_ls_prof_wR_factor _pd_proc_ls_prof_wR_expected
Rietveld/profile fit R factors.
Note that the R factor computed for Rietveld refinements using the extracted reflection intensity values (often called the Rietveld or Bragg R factor, R~B~) is not properly a profile R factor. This R factor may be specified using _refine_ls_R_I_factor. (Some authors report _refine_ls_R_Fsqd_factor or _refine_ls_R_factor_all as the Rietveld or Bragg R factor. While it is appropriate to compute and report any or all of these R factors, the names "Rietveld or Bragg R factor" refer strictly to _refine_ls_R_I_factor.)
_pd_proc_ls_prof_R_factor, often called R~p~, is an unweighted fitness metric for the agreement between the observed and computed diffraction patterns. R~p~ = sum~i~ | I~obs~(i) - I~calc~(i) | / sum~i~ ( I~obs~(i) ) _pd_proc_ls_prof_wR_factor, often called R~wp~, is a weighted fitness metric for the agreement between the observed and computed diffraction patterns. R~wp~ = SQRT { sum~i~ ( w(i) [ I~obs~(i) - I~calc~(i) ]^2^ ) / sum~i~ ( w(i) [I~obs~(i)]^2^ ) }
_pd_proc_ls_prof_wR_expected, sometimes called the
theoretical R~wp~ or R~exp~, is a weighted fitness metric for
the statistical precision of the data set. For an idealized fit,
where all deviations between the observed intensities and
those computed from the model are due to statistical
fluctuations, the observed R~wp~ should match the expected
R factor. In reality, R~wp~ will always be higher than
R~exp~.
R~exp~ = SQRT {
(n - p) / sum~i~ ( w(i) [I~obs~(i)]^2^ ) }
Note that in the above equations, w(i) is the weight for the ith data point (see _pd_proc_ls_weight). I~obs~(i) is the observed intensity for the ith data point, sometimes referred to as y~i~(obs) or y~oi~. (See _pd_meas_counts_total, _pd_meas_intensity_total or _pd_proc_intensity_total.) I~calc~(i) is the computed intensity for the ith data point with background and other corrections applied to match the scale of the observed data set, sometimes referred to as y~i~(calc) or y~ci~. (See _pd_calc_intensity_total.) n is the total number of data points (see _pd_proc_number_of_points) less the number of data points excluded from the refinement. p is the total number of refined parameters.
_pd_proc_ls_profile_function
CIF
Description of the profile function used to
fit the data set. If a function form is used, it is recommended that the actual equation in TeX, or a programming language, is used to specify the function as well as giving a description. Include the values used for the profile-function coefficients and their s.u.'s.
_pd_proc_ls_special_details
CIF
Additional characterization information relevant to
non-routine steps used for refinement of a structural model that cannot be specified elsewhere.
_PD_REFLN_[PD]
CIF
This section provides a mechanism to identify each peak in the
peak-table section (_pd_peak_) with the phase(s) (_pd_phase_id) and the reflection indices (_refln_index_) associated with the peak. There are no restrictions on the number of phases or reflections associated with an observed peak. Reflections may also be included that are not observed; use '.' for the _pd_refln_peak_id.
_PD_SPEC_[PD]
CIF
This section contains information about the specimen used
for measurement of the diffraction data set. Note that information about the sample (the batch of material from which the specimen was obtained) is specified in _pd_prep_.
Example:
_pd_spec_mounting ? _pd_spec_mount_mode transmission _pd_spec_orientation horizontal _pd_spec_preparation ?
_pd_spec_description
CIF
A description of the specimen, such as the source of the
specimen, identification of standards, mixtures etc.
_pd_spec_mount_mode
CIF
A code describing the beam path through the specimen.
_pd_spec_mounting
CIF
A description of how the specimen is mounted.
Examples:
vanadium can with He exchange gas
quartz capillary
packed powder pellet
drifted powder on off-cut Si
drifted powder on Kapton film
_pd_spec_orientation
CIF
The orientation of the () and 2 axis.
Note that this axis is parallel to the specimen axial axis and perpendicular to the plane containing the incident and scattered beams.
Thus for a horizontal orientation, scattering measurements are made in a plane perpendicular to the ground (the 2 axis is parallel to the ground); for vertical orientation, scattering measurements are made in a plane parallel with the ground (the 2 axis is perpendicular to the ground). `Both' is appropriate for experiments where measurements are made in both planes, for example using two-dimensional detectors.
_pd_spec_preparation
CIF
A description of the preparation steps for producing the
diffraction specimen from the sample. Include any procedures related to grinding, sieving, spray drying etc. For information relevant to how the sample is synthesized, use the _pd_prep_ entries.
Examples:
wet grinding in acetone
sieved through a 44 micron (325 mesh/inch) sieve
spray dried in water with 1% clay
_pd_spec_shape
CIF
A code describing the specimen shape.
_pd_spec_size
CIF
Data names: _pd_spec_size_axial _pd_spec_size_equat _pd_spec_size_thick
The size of the specimen in three mutually perpendicular
directions in millimetres. The perpendicular to the plane containing the incident and scattered beam is the *_axial direction. In transmission geometry, the scattering vector is parallel to *_equat and in reflection geometry the scattering vector is parallel to *_thick.
_pd_spec_special_details
CIF
Descriptive information about the specimen that cannot be
included in other data items.
PD_CALIBRATION
CIF
_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_ to define a pointer to the file or data block containing the information used to define this function.
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_calib_ items.
PD_MEAS_INFO
CIF
_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.
_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.
_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.
_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.
_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.
PD_MEAS_METHOD
CIF
_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_.
_pd_meas_2theta_range
CIF
Data names: _pd_meas_2theta_range_min _pd_meas_2theta_range_max _pd_meas_2theta_range_inc
The range of 2 diffraction angles in degrees 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.
_pd_meas_datetime_initiated
CIF
The date and time of the data-set measurement. Entries follow
the standard CIF format 'yyyy-mm-ddThh:mm:ss+zz'. Use of seconds and a time zone is optional, but use of hours and minutes is strongly encouraged. Where possible, give the time when the measurement was started rather than when it was completed.
Example:
1990-07-13T14:40
_pd_meas_number_of_points
CIF
The total number of points in the measured
diffractogram.
_pd_meas_rocking_axis
CIF
Description of the axis (or axes) used to rotate or rock the
specimen for better randomization of crystallites
(see _pd_meas_rocking_angle).
_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.
_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.
_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_.
Examples:
estimated from strip chart
arbitrary, from film density
counts, with automatic dead-time correction applied
PD_PEAK_METHOD
CIF
_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.
PD_PROC_INFO
CIF
_pd_proc_2theta_range
CIF
Data names: _pd_proc_2theta_range_min _pd_proc_2theta_range_max _pd_proc_2theta_range_inc
The range of 2 diffraction angles in degrees for the
measurement of intensities. These may be used in place of the
_pd_proc_2theta_corrected values, or in the case of white-beam
experiments it will define the fixed 2 value.
_pd_proc_info_author_address
CIF
The address of the person who processed the data.
If there is more than one person, this will be looped with
_pd_proc_info_author_name.
_pd_proc_info_author_email
CIF
The e-mail address of the person who processed the
data. If there is more than one person, this will be looped
with _pd_proc_info_author_name.
_pd_proc_info_author_fax
CIF
The fax number of the person who processed the data.
If there is more than one person, this will be looped with
_pd_proc_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.
_pd_proc_info_author_name
CIF
The name of the person who processed the data, if different
from the person(s) 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.
_pd_proc_info_author_phone
CIF
The telephone number of the person who processed the data.
If there is more than one person, this will be looped
with _pd_proc_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.
_pd_proc_info_data_reduction
CIF
Description of the processing steps applied in the data-reduction
process (background subtraction, -2 stripping, smoothing etc.). Include details of the program(s) used etc.
_pd_proc_info_datetime
CIF
Date(s) and time(s) when the data set was processed.
May be looped if multiple processing steps were used.
Dates and times should be specified in the standard CIF format 'yyyy-mm-ddThh:mm:ss+zz'. Use of seconds and a time zone is optional, but use of hours and minutes is strongly encouraged.
Example:
1990-07-13T14:40
_pd_proc_info_excluded_regions
CIF
Description of regions in the diffractogram excluded
from processing along with a justification of why the data points were not used.
Example:
20 to 21 degrees unreliable due to beam dump
_pd_proc_info_special_details
CIF
Detailed description of any non-routine processing steps
applied due to any irregularities in this particular data set.
_pd_proc_number_of_points
CIF
The total number of data points in the processed diffractogram.
REFLN
CIF
_pd_refln_peak_id
CIF
Code which identifies the powder diffraction peak that
contains the current reflection. This code must match a
_pd_peak_id code.
_pd_refln_phase_id
CIF
Code which identifies the crystal phase associated with this
reflection. This code must match a _pd_phase_id code.
_pd_refln_wavelength_id
CIF
Code which identifies the wavelength associated with the
reflection and the peak pointed to by _pd_refln_peak_id.
This code must match a _diffrn_radiation_wavelength_id code.
Revision history
1991-08-28 Initial definitions B.H. Toby
1991-09-15 More definitions added B.H. Toby
1991-09-21 Still More definitions B.H. Toby
1991-09-24 Some updates from down under |:-) S.R. Hall
1991-10-07 Unable to leave well enough alone... B.H. Toby
1991-10-10 Some additional fine tuning (-:| S.R. Hall
1991-10-14 Minor touchups B.H. Toby
1991-12-08 Back to Work... B.H. Toby
1992-01-07 Add _pd_refln_ to allow for mixtures B.H. Toby
1992-02-07 Some redefinitions S.R. Hall
1992-02-25 Defining standards is a fiddly business S.R. Hall
1992-03-18 And still more... B.H. Toby
1992-05-22 Minor cleanup B.H. Toby
1992-05-23 Quasar says that all is OK now... S.R. Hall
1992-05-30 Changes from comments @ APD-II B.H. Toby
1992-08-18 Add calculated pattern definitions B.H. Toby
1992-08-28 Change 'powder' to 'pw' B.H. Toby
1992-08-31 Major overhaul of some definitions B.H. Toby
1992-09-01 Small adjustments S.R. Hall
1992-10-01 Change 'pw' to 'pd' B.H. Toby
1993-04-16 Change usage for multiple detectors B.H. Toby
1993-04-19 Change *_raw_ to *_meas_; *_sample_ to *_samp_
Install new DDL commands; new *_phase_ group S.R. Hall
1993-05-22 Fix _pd_calib_ defs; Minor editing B.H. Toby
1993-05-31 Still more minor editing B.H. Toby
1993-06-02 Application of new DDL commands S.R. Hall
1993-08-13 Last stop before Beijing, more descriptive entries &
more descriptive text added; support for film data. B.H. Toby
1993-10-27 My two cents worth I.D. Brown
1994-01-23 Change two to 2.5; sample to specimen. B.H. Toby
1994-03-13 Change date/time usage
Be more careful about pd_proc usage: separate data
& processing conditions B.H. Toby
1994-04-11 Start work on categories: move all diffractogram
items (that might ever be in a single loop) into
pd_data. B.H. Toby
1994-05-11 Start revisions based on I.D. Brown's comments B.H. Toby
1994-06-25 Complete revisions prior to ACA B.H. Toby
1994-10-27 Working draft B.H. Toby
1995-10-23 Implemented _units and _units_detail B. McMahon
1995-10-24 Transferred _pd_instr_radiation_probe to the core
as _diffrn_radiation_probe B. McMahon
1997-01-30 Final cleanup: removed _nm units; add units to definitions; add _pd_block_diffractogram_id; change _pd_meas_distance_value to _pd_meas_position; remove _pd_proc_wavelength_nm, _pd_proc_d_spacing_nm; _pd_proc_recip_len_Q_nm, and _pd_peak_d_spacing_nm B.H. Toby
1997-01-31 Changed dictionary_definition to category_overview;
removed data_include_dependent_dictionaries and global_
blocks; some typos fixed B. McMahon
1997-02-12 Some typos fixed B. McMahon
1997-02-18 References to e.s.d. changed to s.u. etc.
Notation for Bragg and expected R factors changed to
R~B~ and R~exp~
B. McMahon
1997-03-10 Category of _pd_refln_ things changed to 'refln'; category of` _pd_proc_number_of_points changed to 'pd_proc_info'; some rewording of descriptions involving s.u.s according to BT; changed 'samp' to 'spec' in many datanames relating distances to specimen; changed style of these and similar to *_src/spec etc; _pd_calc_method no longer has '_list yes'; _list_uniqueness deleted from _pd_refln_peak_id; use of '.' instead of '?' recommended in a couple of places; addition of example to _pd_calib_conversion_eqn; '_pd_proc_intensity_calc_bkg' and '_fix_bkg' changed to '_pd_proc_intensity_bkg_calc' and '_fix' B. McMahon
1997-03-12 Category of _pd_calib_ things changed to 'pd_calib';
_pd_calib_conversion_eqn and *_special_details renamed as
_pd_calibration_* and assigned to category 'pd_calibration'
Alphabetised entries within category.
B. McMahon
1997-03-17 Copyediting changes to punctuation and spelling. B. McMahon
1997-10-29 Changed _pd_calib_std_external_id to _pd_calib_std_external_block_id. Moved _pd_proc_2theta_range_ to category pd_proc_info (because not looped with other pd_data items). B. McMahon
1997-10-29 Release version 1.0 B. McMahon
2005-01-07 NJA: minor corrections to hyphenation, spelling and punctuation pd_data_[pd]: Example 3, second loop _pd_calc_2theta_scan changed to _pd_proc_2theta_corrected _pd_instr_cons_illum_len: definition rephrased _pd_phase_[pd]: first sentence of definition rephrased _pd_proc_ls_background_function: second paragraph of definition rephrased