Proposal to define data names for atomic analysis information

[James H]

Dear Core CIF dictionary maintenance group:

A proposal has been developed by some powder people to include results of
sample analysis for atomic content in CIF files. It seems to me that this
is more general than just powder, so I have transferred to proposal to the
CIF core dictionary issues list. Please read through
https://github.com/COMCIFS/cif_core/issues/304 and add your comments there
or here. For reference, the final comment on that issue, which gives the
flavour of the proposal, is reproduced below.

best wishes,
James.
=================================

Given the desire to allow general details of techniques to be included, we
will need one or more separate categories. One alternative is to bundle all
details of techniques into a general purpose category, in the example below
it is ATOM_ANALYTICAL_TECHNIQUE

Here is an example of how this would appear in the CIF file (adapted from
above):

data_block1
loop_
_atom_analytical.id
_atom_analytical.atom_type
_atom_analytical.chemical_species
_atom_analytical.analytical_mass_percent
_atom_analytical.chemical_species_mass_percent
_atom_analytical.technique_id  #<- refers to an _atom_analytical_technique.id
1  Si  SiO2   ?     22.7  XRF
2  Al  Al2O3  ?     27.4  XRF
3  Ti  TiO2   ?      2.7  XRF
4  Si  .      10.5  .     ICP
5  Si  Si     11.7  11.7  EDS

loop_
_atom_analytical_technique.id        #<- this could be a run id if
more than one performed
_atom_analytical_technique.type    #XRF/ICP/EDS etc.
_atom_analytical_technique.special_details
XRF   XRF
;
The loss on ignition at 1000 °C was 12.4 wt%
;

#...

The other alternative, and the one most conducive to expansion in the
future, is to define categories for each analytical technique. These can
remain largely empty until others want to fill them in. So the above would
become:

loop_
_atom_analytical.id
_atom_analytical.atom_type
_atom_analytical.chemical_species
_atom_analytical.analytical_mass_percent
_atom_analytical.chemical_species_mass_percent
_atom_analytical.technique_type
1  Si  SiO2   ?     22.7  XRF
2  Al  Al2O3  ?     27.4  XRF
3  Ti  TiO2   ?      2.7  XRF
4  Si  .      10.5  .     ICP
5  Si  Si     11.7  11.7  EDS

_atom_analytical_XRF.mass_loss_percent    12.4
_atom_analytical_XRF.ignition_temperature   1000

Of these I strongly prefer the second as it ensures that the minimum amount
of information is hidden in machine-opaque text.
-- 
T +61 (02) 9717 9907
F +61 (02) 9717 3145
M +61 (04) 0249 4148
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