[Pw_forum] Re : Re:Pseudopotential for Li

[Bertrand SITAMTZE]

> Message: 7
> Date: Wed, 26 Aug 2009 21:56:44 +0200 (CEST)
> From: "Lorenzo Paulatto" <paulatto at sissa.it>
> Subject: Re: [Pw_forum] Pseudopotential for Li
> To: "PWSCF Forum" <pw_forum at pwscf.org>
> Message-ID: <54147.78.12.159.112.1251316604.squirrel at webmail.sissa.it>
> Content-Type: text/plain;charset=iso-8859-1
> 
> 
Dear Lorenzo
Thank very much for your answer,

> I'll try to give you some hint, but without knowing the
> details of your
> calculation there is no much one can say.
> 
> On Wed, August 26, 2009 19:28, Bertrand SITAMTZE wrote:
> >  I want to use a pseudopotential for Li+ ion and
> I am facing the following
> >  problems with the ld1.x code:
> 
> Why are you not using one of the 15 lithium
> pseudopotentials from the web
> site? <http://www..quantum-espresso.org/pseudo/1.3/html/Li.html>

I wanted to use the Li.pw91-s-van_ak.UPF. But, as we all know, this has to be tested.For this purpose I calculated the bulk properties of bcc lithium (lattice parameter and bulk modulus) and got good result. But I don't know how to regenerate the all electron and pseudo wavefunctions starting with the pseudopotential himself, in order to confirm the test. That is why I decided to generate a pseudopotential by myself. Do you know about this regeneration process?

> On Wed, August 26, 2009 19:28, Bertrand SITAMTZE wrote:
> >   why this problem?
> 
> probably an unreasonable choice for the core charge cutoff
> radius. The
> default value is better than nothing, but does not work in
> all cases.

I used the default value

> >  Can somebody explain this to me?
> 
> Sign of wavefunctions is irrelevant. It is the square
> modulus that has a
> physical meaning.

This remark is welcome. To my understand, I shouldn't care about the sign and for plotting, use the opposite for exact matching!

> >  3) Considering nlcc is only possible if I start
> with the configuration
> >    1s2 2s1.0 2p0.0, which is far from Li+.
> Despite this, I still get a
> >    positive  pseudo-2s wawefunction.
> why?
> 
> I don't understand this question. You can do a
> pseudopotential with 1s2
> 2s0, it won't have nay electron in valence, but should
> still work. BTW,
> all
> 
> 
> -- 
> Lorenzo Paulatto
> SISSA  &  DEMOCRITOS (Trieste)
> phone: +39 040 3787 511
> skype: paulatz
> www:   http://people.sissa.it/~paulatto/



 
 *********************************
Bertrand SITAMTZE
PhD student
Department of physics
University of Yaounde I-Cameroon
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