[Pw_forum] new bfgs: strange behavior doing vc-relax
Paolo Giannozzi
giannozz at democritos.it
Wed Apr 20 17:46:18 CEST 2011
On Apr 20, 2011, at 16:02 , Eduardo Ariel Menendez Proupin wrote:
> I am not sure if the calculation is still variational with
> ultrasoft pseudopotentials
it should be
> or even if the Hohenberg-Kohn lemma is valid with non local
> pseudopotentials
there is some old work by Gilbert on this subject: http://prb.aps.org/
abstract/PRB/v12/i6/p2111_1
> With QE I have always seen the energy to decrease when the cutoffs are
> increased, but with VASP, I always see an oscillation in the total
> energy
> when the cutoff is incremented.
just guessing: it might be a consequence of real-space treatment of
augmentation
functions.
P.
---
Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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