Existing PD categories that need `_pd_phase.id` and/or `_pd_diffractogram.id`-type data items?

[rowlesmr]

Prompted by @briantoby asking a question in https://github.com/COMCIFS/Powder_Dictionary/issues/56#issuecomment-1377538092:

What other categories in the pdCIF dictionary require _pd_phase.id and/or _pd_diffractogram.id-related datanames?

I had a quick look and think at least these are necessary to have one or both:

• PD_CALIB_D_TO_TOF
• PD_INSTR
• PD_INSTR_DETECTOR
• PD_MEAS_INFO_AUTHOR
• PD_MEAS_OVERALL
• PD_PEAK
• PD_PEAK_OVERALL
• PD_PREF_ORIENT
• PD_PROC_INFO_AUTHOR
• PD_PROC_LS
• PD_PROC_OVERALL

I think there are more Set (and probably Loop) categories that might need them. For instance how can we provide some PD_SPEC information, and then link that to multiple diffractograms (eg for the Aussietron PD beamline where you get (at least) two diffraction patterns per specimen) without having to repeat that information.

.

or should this wait while CIF_CORE figures out the requirements on id values for Set categories, and the like?

[jamesrhester]

I think it is OK to go ahead and add these data items to those pdCIF categories.

It is entirely possible that certain CIF_CORE categories will also require child data names of _pd_phase.id and/or _pd_diffractogram.id to be added. The way to do this is simply to include the updated category definition in pdCIF, together with the new data names. There is no need to include definitions of other data names from the CIF_CORE category if the definition changes only by the addition of "for the given phase" or "for the given diffraction pattern" etc.

Such additions to the core categories will probably require CIF_CORE to sort itself out first.

[rowlesmr]

OK. I'll start thinking only about pdCIF categories first.

Re the "updated category definition in pdCIF", is that the same process as done with REFLN?

[jamesrhester]

Yes.