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vdW-dF Change parameters?

Posted: Sat Mar 08, 2014 10:57 pm
by novoselov
Greetings,
Im currently using vdW-dF in vasp.
I know that PBE, revPBE and optPBE use the same enhancement factor but with different numerical parameters.
Is there a way that I could modify those parameters ?

Thanks

vdW-dF Change parameters?

Posted: Tue Mar 11, 2014 1:56 pm
by kelum
Hi,
you need to go into xclib_grad.F, subroutine EXCHPBE and change the
parameters manually there (um and uk).
optPBE has a slightly different enhancement factor, it is a mixture of PBE
and RPBE factors with the same values of mu and kappa and a mixing factor.
(It's explained in the optPBE paper.)
j