[CPMD-list] Na PP

[Axel Kohlmeyer]

On Sun, 11 May 2008, Jiten wrote:

JS> Thanks Axel for the reply.
JS> 
JS> There are two PP available in the pplib directory Na_MT_NLCC.psp 
JS> Na_SEMI_BLYP.psp presumably could be used with the BLYP (both are 
JS> nornconserving types). As there is no ref in the PP info, I wonder which one 
JS> is used in the J. Am. Chem. Soc. 2000, 122, 4837-4838 article.

it could be neither. there are plenty pseudopotentials in use
that are not available from www.cpmd.org for a number of reasons.

however, you can rule out the Na_MT_NLCC.psp for certain, if you
have a look at the &ATOM section. it hast ZV=1, i.e. only one electron
in valence. this pseudopotential can only be used for metallic sodium.
furthermore it has the XC code 1100, which stands for pade type LDA 
(the latter two zeros indicate no gradient correction). for BLYP this
code has to be 1312 as you can easily see from Na_SEMI_BLYP.psp.
_this_ one has nine valence electrons, so it is suitable for sodium
ions. as written before, it does _not_ indicate that this very 
pseudopotential was used, only that it is similar.

JS> It will be really nice if Hutter could give an advice in this regard.

why don't you contact the principal author of the paper, chris mundy?
he is working at pacific northwest national labs in richland, wa now.

cheers,
   axel.

JS> 
JS> Sincerely,
JS> 
JS> Jiten
JS> ----- Original Message ----- 
JS> From: "Axel Kohlmeyer" <akohlmey at cmm.chem.upenn.edu>
JS> To: "Jiten" <jiten at postech.ac.kr>
JS> Cc: <cpmd-list at cpmd.org>
JS> Sent: Saturday, May 10, 2008 7:04 PM
JS> Subject: Re: [CPMD-list] Na PP
JS> 
JS> 
JS> > On Sat, 10 May 2008, Jiten wrote:
JS> >
JS> > JS> Dear CPMD users,
JS> >
JS> > dear jiten,
JS> >
JS> > JS> In J. Am. Chem. Soc. 2000, 122, 4837-4838 (Christopher J. Mundy,
JS> > JS> Ju¨rg Hutter, and Michele Parrinello) abou the Na-water clusters, it
JS> > JS> says that
JS> >
JS> > JS>
JS> > JS> "Norm-preserving pseudopotentials were used to describe the oxygen,
JS> > JS> hydrogen, and sodium cores. In the case of Na, the 2s2-2p6-3s1
JS> > JS> electrons were included explicitly."
JS> > JS>
JS> >
JS> > JS> I am just wondering if I need to do anything with the Na PP
JS> > JS> (Na_SEMI_BLYP.psp) for this purpose.
JS> >
JS> > i don't quite understand the question. which electrons are put into
JS> > valence or not is decided when constructing the pseudo-potential and
JS> > you cannot change it. the label "semi" indicates that the potential
JS> > in question does meet the same requirements as the one in the paper.
JS> >
JS> > the only options that you can vary are the choice of local potential
JS> > and the cutoff. and from looking at similar potentials, i would suspect
JS> > that i will be a "hard" potential and that it is quite possible
JS> > the default LOCAL=P will give you ghost states...
JS> >
JS> > cheers,
JS> >    axel.
JS> >
JS> > JS>
JS> > JS> Any comment is appreciated.
JS> > JS>
JS> > JS> Sincerely,
JS> > JS>
JS> > JS> N. Jiten Singh
JS> > JS> C/O Prof. Kwang S. Kim
JS> > JS> Department of Chemistry
JS> > JS> Pohang University of Science and Technology
JS> > JS> San 31, Hyojadong, Namgu
JS> > JS> Pohang 790-784, Korea
JS> > JS> Phone : 82-54-279-5853 ( Lab ) / 279-4138 ( Appt )
JS> > JS> Fax : 82-54-279-8137 (or +82-54-279-3399)
JS> > JS> Web : http://csm.postech.ac.kr/ and http://www.postech.ac.kr/e
JS> > JS> Home Page : http://www.geocities.com/njs_19
JS> >
JS> > -- 
JS> > =======================================================================
JS> > Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
JS> >   Center for Molecular Modeling   --   University of Pennsylvania
JS> > Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
JS> > tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
JS> > =======================================================================
JS> > If you make something idiot-proof, the universe creates a better idiot. 
JS> 
JS> 
JS> 
JS> 
JS> 
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-- 
=======================================================================
Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
   Center for Molecular Modeling   --   University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
=======================================================================
If you make something idiot-proof, the universe creates a better idiot.