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
