[Pw_forum] Pseudopotentials for Pseudo-Hydrogens

[Gabriele Sclauzero]

> Here's my question. I know that it's problematic to mix different kinds of
> PP's in the same calculation,

What do you mean by different kinds? You can safely mix ultrasoft and norm-conserving PPs, for instance.

You cannot mix different exchange-correlation functionals, obviously.

> and, of course, pw.scf gives a fatal error
> when I try.

Of course it does, but just because it is wrong (not just "problematic") to mix PPs made for different XC functionals.

> Will I get into trouble if I override this by using
> input_dft='pw91', so that I can use the PZ PP's for the pseudo-H's ?  

This would be "incautious", to use an euphemism... 
 
> I'm
> interested mainly in adsorption energies, which are the differences in
> energies between bare and adsorbate-covered slabs. Will any errors incurred
> by mixing PP's cancel in the difference.

There are no additional errors from "mixing" PPs of same XC functional other than those coming from the intrinsic PP approximations.

HTH

GS

> 	As always, thanks for your help and advice.
> 
> Victor M. Bermudez
> Code 6876
> U.S. Naval Research Laboratory
> 4555 Overlook Ave., S.W.
> Washington, DC 20375-5347


§ Gabriele Sclauzero, EPFL SB ITP CSEA
   PH H2 462, Station 3, CH-1015 Lausanne







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