[Pw_forum] info Raman spectrum

[Filipe Camargo Dalmatti Alves Lima]

Since I had lots of problems before I am sending you very useful comments
on Raman calculations:

IF you are calculating a system that has metal atoms when you setup
epsil=.true.
in your input file, you can receive this error:

 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%
     from phq_readin : error #         1
     no elec. field with metals
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%

If it happened to you, just follow the professor Paolo Giannozzi
suggestions (I am pasting his e-mail below, when he replied in 2012):

#############################################################
it is not sufficient: the code cannot calculate the dielectric
tensor for what appears to be a metal (even if it isn't).
A simple solution might be to perform a calculation with
fixed occupancies read from input, starting from the
self-consistent charge density, before the phonon
calculation

P.
---
Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
###############################################################

I hope you won't have the same problems I had 2 years ago.

Best regards and good Raman spectrum calculations,

Filipe


On Fri, Aug 22, 2014 at 10:19 AM, xirainbow <nkxirainbow at gmail.com> wrote:

> > - which kind of pseudopotential  should i use? ultrasoft or norm
> conserving?;
>           Only norm conserving.
>
> >   •relaxed the structure (pw.x);
> >   •scf of the structure with the new positions (pw.x);
> >   • ph.x with <lraman> turn on;
> >   • used dynmat.x for obtaining the frequencies mode.
>                yes.
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
>



-- 
_________________________________________
Filipe Camargo Dalmatti Alves Lima
PhD Student
University of São Paulo, Physics Institute, Materials Physics Department,
Nanomol Group, Brazil.
Phones:    (11) 3091-6881  (USP)
                (11) 97408-2755 (Vivo)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20140822/525ad060/attachment.html>