[Pw_forum] 'Tetrahedra' and 'scf'

[Максим Попов]

Dear Prof. Giannozzi,

first of all, I'm sorry for the typo. Thank you for the quick reply too!
It is true that Hellmann-Feynman theorem does not work for the tetrahedron
method,
but for scf it should not be a problem. Should it?

2010/10/27 Paolo Giannozzi <giannozz at democritos.it>

> Максим Попов wrote:
>
> > according to changelog-4.2, the tetrahedron method was forbidden to be
> > used for scf at *2010-03-25.*
> > What is the reason?
>
> forces are not variational, i.e. are not the derivative of the energy.
> This shouldn't be a big problem if you do not calculate forces, though.
>
> >  Probably, the best person to answer the question is Prof. Gianozzi.
>
> I don't know any Prof. "Gianozzi". Who is he?
>
> P.
> --
> Paolo Giannozzi, Democritos and University of Udine, Italy
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-- 
Best regards, Max Popov
Ph.D. student
Materials center Leoben (MCL), Leoben, Austria.
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