[Pw_forum] utilization of different Ultrasoft pseudopotentials

[Axel Kohlmeyer]

On Fri, 2009-03-27 at 15:17 +0100, Marcel Mohr wrote:
> On Fri, 27 Mar 2009, saqib.javaid at ipcms.u-strasbg.fr wrote:
> 
> >
> > Dear PWSCF users,
> > I have question regarding utilization of different type of Ultrasoft
> > pseudopotentials. Is it correct to use different type of ultrasoft PS ( like
> > rrkjus and Vanderbilt) for different atoms in a given system??? (e.g. one can
> > use rrkjus PS of Cobalt and Vanderbilt PS of Mn with same XC functionals in a
> > given system)
> 
> There is a similar question from beginning of this month, and the answer I 
> remember is yes, as long as they use the same XC functional (as you 
> stated)
> 
> However I got a question arising from this, too.
> 
> Why are rrkj pseudos sometimes called ultrasoft?

this was referring to "rrkjus" which are indeed ultrasoft.
note the additional "us".

axel.

>   In the book by Richard 
> Martin the terms "ultra-soft" and "norm-conserving" are opposites, so only 
> Vanderbuilt pseudos or (PAW) are "ultrasoft".
> However Troullier-Martins and rrkj are norm-conserving and thus I 
> conclude "not" ultrasoft ?!
> 
> I would greatly acknowledge any comment.
> 
> Cheers
> Marcel
> 
> 
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-- 
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Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
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