[Pw_forum] How to generate a pp which is 3/4 of itself using virtual.x

[Jun Dai]

Prof. Baroni and Prof Isaev,
Thanks for your replies,
my original idea is something like using virtual.x to mix a O pp with a ghost pp to generate a new O pp which has 3/4 of O
to stand for of the 3/4 occupation. Like those in alloys AxB1-xs, if I take a ghost pp as A, and the original O pp as B. Is it possible or reasonable?

Bests

Jun DAI

============================================

Ph.D. Candidate,
Hefei National Laboratory For Physical Sciences at the Microscale,
University of Science and Technology of China,
Hefei, Anhui, 230026,
People's Republic of China
Tel.: 86-551-3606428
Fax.: 86-551-3602969
E-mail: jdai3 at mail.ustc.edu.cn
============================================




> -----Original E-mail-----
> From: "Eyvaz Isaev" <eyvaz_isaev at yahoo.com>
> Sent Time: 2009-10-19 6:11:02
> To: "PWSCF Forum" <pw_forum at pwscf.org>
> Cc: 
> Subject: Re: [Pw_forum] How to generate a pp which is 3/4 of itself using
	virtual.x
> 
> Dear Jun Dai,
> 
> --- On Sun, 10/18/09, Jun Dai <jdai3 at mail.ustc.edu.cn> wrote:
>  
> > I have a system has 38 oxygen atoms whoes occupation is 3/4, so i want 
> > to genrate a new O pp which is 3/4 of itself, 
> > can someone give some suggestions on how to do it,
> 
> I suggest, the problem has no solution in ab initio calculations. What you mean generating of a new PsP for O (3/4 of O) means to generate a PsP ... for  Carbon. Using virtual.x you can mix PsPs for elements with similar properties or neighbouring elements in the Periodic Table.  
> 
> But the problem you post is different: an O position is occupied by the probability of 0.75. I think the problem can not be solved also in the framework of alloy's theory where a site can be occupied in accordance with atomic concentration (but the site occupancy is 1!), say in a substitutional alloy A(1-x)B(x)C, where atoms A and B occupy the same site with weight 1-x and x, respectively.
> 
> Hope this helps.
> 
> Bests,
> Eyvaz.
> 
> -------------------------------------------------------------------
> Prof. Eyvaz Isaev, 
> Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, 
> Department of Physics, Chemistry, and Biology (IFM), Linkoping University, Sweden 
> Condensed Matter Theory Group, Uppsala University, Sweden 
> Eyvaz.Isaev at fysik.uu.se, isaev at ifm.liu.se, eyvaz_isaev at yahoo.com
> 
> 
> 
> 
> 
>       
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