[Pw_forum] Res: vc-relax, GGA
asafis at yahoo.com.br
Tue Aug 24 19:44:09 CEST 2010
Hello, Guda. The errors in the determination of lattice parameters (a, b, c,
alpha, beta and gamma) are 1.5%, 0.9%, 1.6%, 0.7%, 0.04% and 2.1%,
respectively. But the problem is that the value found for the alpha angle is
slightly lower than the experimental value despite being GGA functional. In
this case, all or not should not be overestimated?
A. S. Santos
Univesidade Federal Fluminense
Niterói-Rio de Janeiro-Brasil
De: Guda Karthik <karthik.guda at gmail.com>
Para: PWSCF Forum <pw_forum at pwscf.org>
Enviadas: Terça-feira, 24 de Agosto de 2010 13:57:17
Assunto: Re: [Pw_forum] vc-relax, GGA
GGA results tend to overestimate the lattice parameters where as LDA results
tend to underestimate the lattice parameters. Check how much is the error% in
your DFT calculations.
On Tue, Aug 24, 2010 at 12:35 PM, Álvaro Alves <asafis at yahoo.com.br> wrote:
Hello PWscf users. I optimize a triclinic cell using the vc-relax, GGA
functional. My expectation was that all values of the calculated parameters were
slightly higher than the respective experimental values. But, the angle alpha
showed a value slightly lower. The experimental value is in degree, 103.32, the
calculated value is 102.6. There is some inconsistency in this result?
>A. S. Santos
>Univesidade Federal Fluminense
>Niterói-Rio de Janeiro-Brasil
>Pw_forum mailing list
>Pw_forum at pwscf.org
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