[CPMD-list] about POPULATION ANALYSIS

[Axel Kohlmeyer]

On Mon, 31 Mar 2008, Xiandong Liu wrote:

XL> Dear CPMD users,

dear xiandong,

XL>   I want to do POPULATION ANALYSIS with a silicate material. I am
XL> using the following psps:
XL>  O_MT_BLYP.psp
XL>  H_MT_BLYP.psp
XL>  Si_MT_BLYP.psp
XL>  Al_MT_GIA_BLYP.psp
XL>  Fe_MT_BLYP_NLCC.psp
XL> .
XL> Since CPMD has two methods, i.e. MULLIKEN and DAVIDSON, which one is
XL> better for my system ?

hard to say. probably none. ;)

population analysis always has to be taken with a large grain
of salt and with plane waves even more so, since you first
project on an atomic basis (which is always incomplete).

XL> Furthermore, in &BASIS section, does PSEUDO AO mean the
XL> pseudo-wavefunctions used in calculation ?

please see the manual for a detailed explanation.
PSEUDO AO instructs CPMD to use the pseudo wavefunctions
stored in numerical pseudopotentials instead of the
minimal slater functions stored internally. those are
used in two places, for creating the initial atomic guess
and for the projections.

XL> In my understanding, when I use the following set for Al,
XL> *Al_MT_GIA_BLYP.psp KLEINMAN-BYLANDER
XL>  LMAX=D LOC=0
XL> Then I should set the PSEUDO AO as
XL> PSEUDO AO 3
XL>  0 1 2

correct.

XL> when I use the following for oxygen,
XL> *O_MT_BLYP.psp KLEINMAN-BYLANDER
XL>  LMAX=P
XL> Then I should set it as
XL> PSEUDO AO 2
XL>  0 1

also correct.

the real tricky one is the iron pseudo. :)
did you see the comment in the &INFO section?

cheers,
   axel.

XL> Is this right ?
XL> 
XL> Thanks for your suggestions.
XL> 
XL> 
XL> BEST
XL> 
XL> Xiandong
XL> _______________________________________________
XL> CPMD-list mailing list
XL> CPMD-list at cpmd.org
XL> http://cpmd.org/mailman/listinfo/cpmd-list
XL> 

-- 
=======================================================================
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
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