[Pw_forum] TB09 metaGGA

[Paolo Giannozzi]

Actually I think I know why this happen: numerical noise 
in regions of low charge density, but I don't know how to 
fix it

Paolo

On Fri, 2014-11-07 at 09:50 +0100, Juanjo Meléndez wrote:
> Thank you, Paolo. I will keep working on this...
> 
> Juanjo
> 
> 
> Juan J. Meléndez
> Associate Professor
> Department of Physics · University of Extremadura
> Avda. de Elvas, s/n 06006 Badajoz (Spain)
> Phone: +34 924 28 96 55
> Fax: +34 924 28 96 51
> Email: melendez at unex.es
> Web: http://materiales.unex.es/miembros/personal/jj-melendez/Index.html
> 
> 
> -----Mensaje original----- 
> From: Paolo Giannozzi
> Sent: Thursday, November 06, 2014 7:15 PM
> To: PWSCF Forum
> Subject: Re: [Pw_forum] TB09 metaGGA
> 
> I don't remember if non-scf for metaGGA is implemented: if you
> get funny results, it is likely that it isn't. Problem is, one
> often gets funny results also in scf calculations, in all but
> the simplest systems. Never found why.
> 
> Paolo
> 
> On Wed, 2014-10-29 at 19:50 +0100, Juanjo Meléndez wrote:
> > Hi all
> >
> > I am starting to work with metaGGA functionals in QE (v. 5.1 + libXc),
> > following Èric Germaneau and colleagues’ work
> > (http://dx.doi.org/10.1016/j.cpc.2013.02.020). I know that metaGGA is
> > little tested, but I would be pleased if somebody could answer a
> > couple of questions:
> >
> > 1) Convergence is quite tricky. Up to know, I got some results in
> > simple systems using a very small mixing_beta (within 0.01–0.05), not
> > too many bands (just one or two conduction bands, never converged for
> > more bands) and restarting from a previously fully converged
> > calculation. I got results only for carbon, silicon and germanium,
> > never got any convergence for any binary simple compound (like LiF).
> > Does anyone have additional hints for metaGGA calculations to
> > converge?
> >
> > 2) In addition, I get something wrong with nscf calculations. After
> > convergence of a scf run, I get a list of bands at each k-point, as
> > usual –nothing strange here. Then I made a path of k-points to get the
> > band structure and run a nscf calculation. This finishes fine as well,
> > but the bands are not only different from those from the scf
> > calculations, but also unrealistically high. I am attaching the input
> > and output files for both the scf and nscf runs, as well as a couple
> > of eigenval.xml files taken after nscf. Does anybody know how to
> > manage this? Or could this be a bug in the code?
> >
> > Thanks a lot in advance
> >
> > Take care
> >
> > Juanjo
> >
> > Juan J. Meléndez
> > Associate Professor
> > Department of Physics · University of Extremadura
> > Avda. de Elvas, s/n 06006 Badajoz (Spain)
> > Phone: +34 924 28 96 55
> > Fax: +34 924 28 96 51
> > Email: melendez at unex.es
> > Web:
> > http://materiales.unex.es/miembros/personal/jj-melendez/Index.html
> >
> > ****************************
> > “All those who look stupid actually are, as also are half of those who
> > do not look like” (F. de Quevedo)
> >
> > ****************************
> >
> >
> >
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-- 
 Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
 Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
 Phone +39-0432-558216, fax +39-0432-558222