[Wien] Few questions about onsite hybrids and so

[Pavel Ondračka]

On Mon, 2024-02-12 at 20:57 +0800, Laurence Marks wrote:
> With an RMT for Tb of 2.43 the O2p will leak into the Tb sphere. I
> used 2.02. You may want to use -ecut .995 or simioar rather than a
> fixed energy.

Will try, thanks.

> If your Ga & Tb positions are fixed then I guess -so might work in
> MSR1a, I have never tried.
> 
> N.B., I meant x-ray or neutron positions, the latter might be better
> for the O. In my opinion you should not use peaks in spectra or band
> gaps as these are excited state properties, and -eece is ground
> state. That said, optimizing the hybrid fraction for positions gave
> decent gaps for a few other cases as well. Never published as I have
> no explanation.

I fully agree that comparing band structure to optical spectra (and
optical band gaps) is tricky (unless one can also do BSE). However on
the contrary I have some good experience with XPS valence band
measurements. For example I previously observed good agreement between
position of some occupied defect states in the band gap as calculated
with (full hybrid) DFT and observed by valence band XPS.

Anyway, thanks again for all the suggestions, I'll also check if I can
get good enough O positions from XRD to compare to the relaxed
positions as dependent on the the hybrid fraction...

Best regards
Pavel