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(60) Powder indexing; final call on pdCIF 1.0

  • To: COMCIFS@iucr.ac.uk
  • Subject: (60) Powder indexing; final call on pdCIF 1.0
  • From: bm
  • Date: Fri, 14 Mar 1997 10:43:16 GMT
Dear Colleagues

D59.1 Powder indexing
---------------------
In response to Robin Shirley's indexing proposals, which I posted last time,
Brian T. has already been in correspondence, and I reproduce below part of
the letter he wrote to Robin at the end of January. On this basis I propose
that we proceed with the approval for version 1.0 without additional
indexing terms, but remain open to the submission of a revised proposal,
taking Brian's suggestions into account, for inclusion in version 1.1.

On Jan 29,  5:40pm, Brian H. Toby wrote:
>
> Robin,
>    I would like to also ask you a bit more about the indexing terms you would
> like to see added. I think that it makes sense to have a _pd_indexing_ section
> of definitions added to the dictionary. This will probably be a fair amount of
> work, so this may be best done in a later version of the dictionary. For now,
> here are the definitions used for the peak section (as they appear in the
> actual CIF dictionary).

(omitted)

> _pd_proc_quadr_Q
>
> As we discussed this summer, I would prefer not to include the d-star-squared
> value, as the peak d-space is already present and two are easily
> interconverted.
>
> _pd_index_appendix
>
> Could we use _pd_peak_special_details for this purpose?
>
> _pd_proc_index_merit
>
> We have tried to avoid "catchall" definitions like this. I would prefer to
> have a set of definitions: _pd_index_FOM_ (e.g. _pd_index_FOM_M20) with formal
> definitions for each different indexing figure of merit. What do you think?
> Would you want to prepare a set of definitions at some point? In the short
> term, I would suggest having FOM values listed in _pd_peak_special_details as
> ASCII text as:
> ; Not indexed by ITO. Indexed by TREOR, FOM=26.27 (M20). Unindexed peak at
>   21.1 degrees might be ...
> ;
>
> _pd_peak_index_status
>
> I can see two possible directions here. One is to use the existing _pd_peak_id
> code. Note how one can search the peak table to see if a peak is singly or
> multiply indexed. I could add to the definition for _pd_peak_id that the value
> "?" (CIF for unknown) is to be used for the id where peaks are not indexed.
> The other choice would be to add a new entry. My preference would be
> _pd_peak_indexed which would have values s, m, u, or e for single, multiple,
>  unindexed and excluded. I prefer the former of the two choices, but will
> follow your preference.
>
> Looking forward to your input,
>
> Brian

Version 0.996 of the powder dictionary is now on the web; this differs from
the previous version 0.995 only in the alphabetic reorganisation of terms
within each thematic group. For those who are gluttons for detail, I append
to this message a list of the new order of data blocks.

Beyond any minor changes to grammar and punctuation that might occur in a
final copyediting pass, I consider this version now complete and grant my
own formal approval; I invite a similar affirmation from those few of our
full members who have yet to send in their agreement.

Regards
Brian

Appendix: Ordered list of data blocks in version 0.996

data_pd_block_[pd]
data_pd_block_diffractogram_id
data_pd_block_id

data_pd_meas_[pd]
data_pd_meas_2theta_fixed
data_pd_meas_2theta_range_
data_pd_meas_2theta_scan
data_pd_meas_angle_
data_pd_meas_counts_
data_pd_meas_datetime_initiated
data_pd_meas_detector_id
data_pd_meas_info_author_address
data_pd_meas_info_author_email
data_pd_meas_info_author_fax
data_pd_meas_info_author_name
data_pd_meas_info_author_phone
data_pd_meas_intensity_
data_pd_meas_number_of_points
data_pd_meas_position
data_pd_meas_rocking_angle
data_pd_meas_rocking_axis
data_pd_meas_scan_method
data_pd_meas_special_details
data_pd_meas_step_count_time
data_pd_meas_time_of_flight
data_pd_meas_units_of_intensity

data_pd_calib_[pd]
data_pd_calib_2theta_
data_pd_calib_detector_id
data_pd_calib_detector_response
data_pd_calib_std_external_
data_pd_calib_std_internal_mass_%
data_pd_calib_std_internal_name
data_pd_calibration_conversion_eqn
data_pd_calibration_special_details

data_pd_spec_[pd]
data_pd_spec_description
data_pd_spec_mount_mode
data_pd_spec_mounting
data_pd_spec_orientation
data_pd_spec_preparation
data_pd_spec_shape
data_pd_spec_size_
data_pd_spec_special_details

data_pd_instr_[pd]
data_pd_instr_2theta_monochr_
data_pd_instr_beam_size_
data_pd_instr_cons_illum_flag
data_pd_instr_cons_illum_len
data_pd_instr_dist_
data_pd_instr_divg_ax_
data_pd_instr_divg_eq_
data_pd_instr_geometry
data_pd_instr_location
data_pd_instr_monochr_
data_pd_instr_slit_ax_
data_pd_instr_slit_eq_
data_pd_instr_soller_ax_
data_pd_instr_soller_eq_
data_pd_instr_source_size_
data_pd_instr_special_details
data_pd_instr_var_illum_len

data_pd_proc_[pd]
data_pd_proc_2theta_corrected
data_pd_proc_2theta_range_
data_pd_proc_d_spacing
data_pd_proc_energy_
data_pd_proc_info_author_address
data_pd_proc_info_author_email
data_pd_proc_info_author_fax
data_pd_proc_info_author_name
data_pd_proc_info_author_phone
data_pd_proc_info_data_reduction
data_pd_proc_info_datetime
data_pd_proc_info_excluded_regions
data_pd_proc_info_special_details
data_pd_proc_intensity_
data_pd_proc_number_of_points
data_pd_proc_recip_len_Q
data_pd_proc_wavelength

data_pd_proc_ls_[pd]
data_pd_proc_ls_background_function
data_pd_proc_ls_peak_cutoff
data_pd_proc_ls_pref_orient_corr
data_pd_proc_ls_prof_
data_pd_proc_ls_profile_function
data_pd_proc_ls_special_details
data_pd_proc_ls_weight

data_pd_calc_[pd]
data_pd_calc_intensity_
data_pd_calc_method

data_pd_peak_[pd]
data_pd_peak_2theta_
data_pd_peak_d_spacing
data_pd_peak_id
data_pd_peak_intensity
data_pd_peak_pk_height
data_pd_peak_special_details
data_pd_peak_wavelength_id
data_pd_peak_width_2theta
data_pd_peak_width_d_spacing

data_pd_phase_[pd]
data_pd_phase_block_id
data_pd_phase_id
data_pd_phase_mass_%
data_pd_phase_name

data_pd_refln_[pd]
data_pd_refln_peak_id
data_pd_refln_phase_id
data_pd_refln_wavelength_id

data_pd_prep_[pd]
data_pd_prep_conditions
data_pd_prep_cool_rate
data_pd_prep_pressure
data_pd_prep_temperature

data_pd_char_[pd]
data_pd_char_atten_coef_mu_
data_pd_char_colour
data_pd_char_particle_morphology
data_pd_char_special_details
########################################################################