[CPMD-list] Gaussian Core

[Alessandro Curioni]

Some add on to this discussion :

-you have definetively  to add core charges (or an approximation to it ) 
to  obtain reasonable results of the  Bader analisys - this is a must 
especially if you have systems  that include hydrogens 
-we have done  several Bader related analysis  and results on the valence 
charge distribution are stable  vs  reasonable approximations of the core 
charge added to restore the topology - best thing to do
  is to add back atomic core charges  obtained at pseudopotential 
generation ( you can indeed obtain them very easily), 
 - use gradient following strategy to detrmine the basins on the  total 
density and of course integrate only the valence density
-we have a tool that manipulates  cubefiles ,  add  core charges, and 
extract  attraction basins and charges -   we are planning to put in on 
the cpmd.org site  as soon it  has been cleaned a little bit -   but we 
can share
   it with you if  you are not a maniac of perfect software and can help 
to debug it -


Best,


Alessandro







Axel Kohlmeyer <akohlmey at cmm.chem.upenn.edu> 
Sent by: cpmd-list-bounces at cpmd.org
10/17/2007 06:57 AM
Please respond to
Axel Kohlmeyer <akohlmey at cmm.chem.upenn.edu>


To
EG Kim <eunggun.kim at chemistry.gatech.edu>
cc
cpmd-list at cpmd.org
Subject
Re: [CPMD-list] Gaussian Core






On Tue, 16 Oct 2007, EG Kim wrote:

EGK> Dear List Subscribers,
EGK> 
EGK> I wonder if there's a simple way to write the Gaussian core electron 
density
EGK> into DENSITY along with the usual valence electron density (without 
modifying
EGK> the code!).  I am trying to use a new grid-based Bader analysis 
program

the short answer to this is... no.

EGK> (developed by G. Henkelman at UT Austin).  For the program to work 
correctly, I
EGK> need the charge density maxima (whether real or not) at the atomic 
centers.  I
EGK> am using the latest version of CPMD (3.11).  Thank you very much for 
reading.

depending on what property you are looking for and what
accuracy you expect, you can probably still can get some
useful results with the bader code (it is not _that_ new, btw).

other than that, you'll have to add the core density. in fact, 
if you want it accurately, you'll have to record that during the
generation of the pseudopotentials, i.e. you'll have to build
your own pseudopotentials and potentially hack the atomic code, too.

an easier solution would be to use codes that implement some
version of the PAW method or something equivalent.


cheers,
  axel.
EGK> 
EGK> Regards,
EGK> 
EGK> EG Kim
EGK> 
EGK> _______________________________________________
EGK> CPMD-list mailing list
EGK> CPMD-list at cpmd.org
EGK> http://cpmd.org/mailman/listinfo/cpmd-list
EGK> 

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