Hi John,
> The improved NeXuS format for XAS data looks fine to me. Good idea. But it makes me wonder whether
> a similar formatting for theoretical XAS data would be useful, especially for analysis purposes.
Thanks. That is an interesting question. I don't have an immediate answer.
I think it is not too difficult to read the plain text output files from FEFF and FDMNES. I don't have much experience withther codes. That is, I expect that plain text files with a few labeled columns is probably good enough for "energy" and "calculated mu". I am not at all sure if there could be common ways to label the other parts of the calculation like broadening terms or partial DOS, etc. And, it would be great to be able to extend any conventions to resonant emission/absorption data like RIXS plane or q-dependent X-ray Raman.
But it would be worth discussing this, maybe with other theorists, people doing multiple XANES+DFT++ calculations, and maybe people from the Materials Project.
The situation for experimental data is sort of worse, even for beamlines that mostly collect XAFS and at well-run facilities. Beamline "raw data files" might have 100 columns, and will often vary beamline-by-beamline and sometimes month-to-month. For transmission data, it is often easy to guess how to build mu(E), but for fluorescence data, it is often very hard to know what "the data" is. It's OK if the people using the data know what to do and then publish the reduced data. But as we move (some faster than others) toward being required to make all data available, this is becoming a problem.
But, yes, we want to keep in mind that "experimental plain XAFS data" should not be the only goal.