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?
Sincerely, A. S. Santos Univesidade Federal Fluminense Niter?i-Rio de Janeiro-Brasil ________________________________ De: Guda Karthik <karthik.guda at gmail.com> Para: PWSCF Forum <pw_forum at pwscf.org> Enviadas: Ter?a-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. regards, On Tue, Aug 24, 2010 at 12:35 PM, ?lvaro 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? > >Sincerely, >A. S. Santos > >Univesidade Federal Fluminense >Niter?i-Rio de Janeiro-Brasil > > > > > > > > > >_______________________________________________ >Pw_forum mailing list >Pw_forum at pwscf.org >http://www.democritos.it/mailman/listinfo/pw_forum > > -- Karthik Guda Graduate Student Materials Engineering Purdue University -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20100824/45f4fe7d/attachment.htm
