[CPMD-list] PW91 implementation

[Oleksandr Shepelyev]

Dear Dr. Axel Kohlmeyer,

Thank you very much for the prompt reply. But from the CPMD mailing list
I found that many people had problems with PBE potential, especially for
metals. They had problems with convergence and magnetic moment. I want
to study metal compounds too. So I think that problems could be caused
by mistake in functional which I described in the second part of my
previous letter. Or maybe PBE potential is too simple to describe all
properties of solid phase.

Anyway I think it is not hard to implement one additional functional for
certainly good potential into CPMD. The problem is that realization of
Density Functional Theory in CPMD is different from the routines suggested
by John Perdew (http://dft.rutgers.edu/pubs/PBE.asc).

Sincerely yours,

Alex Shepelyev


> dear oleksandr,
> 
> it might be much easier, if you would recreate the PW91 pseudo-potentials
> for PBE, since the two functionals are so similar. as you can see
> from the vanderbilt pseudopotential code, the parameter exfact determines
> the functional. of course you will have to carefully check and test
> the new pseudopotentials, but since you seem to be starting a new
> project, you would have to do this anyway.
> 
> hope this helps,
> 	axel kohlmeyer.