[Pw_forum] Re: Mg pseudopotential

[CLAUDIA BUNGARO]

Dear Leonardo,

As already mentioned by Stefano De gironcoli, the
pseudopotential Mg.pz-n-vbc.UPF that you can find at the pwscf web page is a
norm-conserving PP with nlcc and it has been used in a number of systems,
including phonons of Mg surfaces (and thermal expansion).
Look at the  details item in the pseudopotential page.

There is a section in the manual about negative Acoustic frequencies at
gamma (troubleshooting). If they are not too large they may just be due to
the fact that the ASR is not IMPOSED in the code.



Claudia Bungaro


__________________________________________________
Dr. Claudia Bungaro
Dept. of Physics and Astronomy, Rutgers University
136 Frelinghuysen Road, Piscataway,  NJ 08854-8019

tel: +1 732 445 4197          fax: +1 732 445 4343
email: bungaro at physics.rutgers.edu
__________________________________________________


On Tue, 5 Apr 2005, Aritz Leonardo wrote:

> Dear Dr. Claudia Bungaro:
>
> Let me present myself. My name is Aritz Leonardo and I am a second year
> phd student at the Donostia International Physics Center under the
> supervision of prof. Eugene Chulkov.
>
> We are performing some electron-phonon calculations of Mg layers, for
> this reason I read your paper titled: "Surface lattice dynamics of
> Mg(0001)" which I found very interesting and helpful.
>
> I am having some trouble with negative frequencies of phonons near gamma
> point and I am almost sure that the problem is the pseudopotential I
> use. I forgot to mention that I use PWscf code for all my calculations.
>
> Would it be possible to have the pseudopotential you used in the paper
> mentioned? (PRB 62, 17012 (2000))
>
> Thanks a lot and I hope this doesn't seem too forward.
>
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> Aritz Leonardo Liceranzu
> tlf: (+34)943015626
> http://dipc.ehu.es/group/index.htm
>