[TCOD] What structures do we accept to TCOD?

[Armel le Bail]

Hi,

> Absolutely! We just need to mark carefully that atomic positions were
> optimised, and cell constants were not.
>
> Something along the lines:
>
> loop_
> _tcod_optimisation_id
> _tcod_optimisation_parameter
> _tcod_optimisation_flag
> 1 cell_constants        no
> 2 atomic_coordinates    yes
> 3 thermal_displacements no # Most probably 'no' for current
>                            # computations, but 'yes' may become common
>                            # in the future
>
> OK?

More ideally, I think that the whole DFT instruction file should
be provided inside of the CIF. As you know, IUCr is now asking
for such refinement instruction details in the following way with
a tag :

_iucr_refine_instructions_details
;
    insert here the SHELX .ins or .res file
    or etc (Rietveld entry file for powders)
;

We could have some specific TCOD tag :

_tcod_optimization_instructions_details
;
   insert here the VASP/WIEN2K/CASTEP/... entry file
;

Of course the software name and the version should be given.
This would allow for some reproducibility test and for example
test files. The fact that cell parameters are optimized or not
(and other details) will appear there.

Best,

Armel

PS - Crystallography (apples) is >100 years old and now some
are considering it as a technic rather than a science. Quantum
Mechanics (bananas) is almost as old but quite younger in its
applications for optimizing/predicting/... matter, so it needs
maybe 100 more years before to be called a technic too ;-).
TCOD may participate to some acceleration in the progress by
allowing access to the complete datafiles.