[CPMD-list] Au pseudopotentials

[Alessandro Curioni]

There is for sure some confusion  about  pseudopotentials -

There is no reason why MT pseudos shouldn't  be able to handle  Transition
Metals  -  (or to handle them in a different way than other norm conserving
pseudos)-
it is simply  a matter of how you build them .  More questionable is the
fact that in Transion metals  the smoothness of MT pseudos  could give some
advantages with
respect to other norm conserving pseudos (i.e you are  forced to use very
small rc  anyway -  therefore to use high cutoff).

Moreover  there is  a big difference between the first row  transition
metals and the others -   MT pseudos for Gold, Platinum have been  build
tested  and used by  our group
extensively and   can  describe  properties going from small clusters,
solids, surfaces and  complexes at  an affordable cutoff.

To Build a good pseudo is  a non trivial task anyway - and require to have
a deep knowledge of the field - of course you can use  pre-gererated
pseudos - but need to test
them extensively - if you want  to produce science and not garbage.

One common problem  that you could have is the  appearance of ghost states
when using the Kleinman-Bylander approx - and usually  one is forced to use
a lower L then the highest one as reference local potential (this is common
to other normconserving PP) -   e.g. if you build the Gold with the  rc in
the JACS paper -
you must use L=S as  local part.  ( see Groeneack et al - Chemical Physics
262 , 1).

Another problem you may encounter is the generation of semicore pseudos  (
as the 11 e- Gold) - many pseudopotentials generation code have problems in
assigning
the right  quantum numbers to the  states when including the n-1 shell in
the valence -  so be careful -


Please let me know if you have still problems -


Best Regards,

Alessandro








Alessandro CURIONI, PhD
Research Staff Member
Computational Biochemistry and Material Science group
IBM Research Division - Zurich Research Laboratory
Saumerstrasse 4
8003 Rueschlikon - Switzerland
e-mail: cur at zurich.ibm.com
www:    www.zurich.ibm.com
Tel: +41-1-7248633
Fax: +41-1-7248958



                                                                           
             Axel Kohlmeyer                                                
             <axel.kohlmeyer at t                                             
             heochem.ruhr-uni-                                          To 
             bochum.de>                cpmd-list at cpmd.org, Stefano Piana   
             Sent by:                  <piana at power.curtin.edu.au>         
             cpmd-list-bounces                                          cc 
             @cpmd.org                                                     
                                                                   Subject 
                                       Re: [CPMD-list] Au pseudopotentials 
             11/30/2004 10:33                                              
             AM                                                            
                                                                           
                                                                           
                                                                           
                                                                           





On Tue, 30 Nov 2004, Stefano Piana wrote:

stefano,

SP> Does anybody has MT and/or Vanderbilt pseudopotentials for Au with the
SP> PBE xc functional?

there is a gold PW91 pseudopotential in the vanderbilt library,
which could be easily adapted to PBE (in fact i already have),
but it is not compatible with CPMD. see
http://www.cpmd.org/pipermail/cpmd-list/2004-November/003803.html

SP> I am trying to generate them with the program of Giannozzi and the
SP> parameters of Gronbeck et al JACS (2000) 122:3839-3842 but the pseudos
SP> that I generate behave a bit weird.

in my experience, troullier-martins pseudopotentials do not always
work so well for transition metals. you may want to try the attached
goedecker-hartwigsen pseudopotential from mauro boero's pseudopotential
collection (done by roger rousseau, AFAIK) instead.

regards,
             axel.

SP> Thanks,
SP>
SP> Stefano
SP>
SP> _______________________________________________
SP> CPMD-list mailing list
SP> CPMD-list at cpmd.org
SP> http://cpmd.org/mailman/listinfo/cpmd-list
SP>
SP>

--

=======================================================================
Dr. Axel Kohlmeyer   e-mail: axel.kohlmeyer at theochem.ruhr-uni-bochum.de
Lehrstuhl fuer Theoretische Chemie          Phone: ++49 (0)234/32-26673
Ruhr-Universitaet Bochum - NC 03/53         Fax:   ++49 (0)234/32-14045
D-44780 Bochum  http://www.theochem.ruhr-uni-bochum.de/~axel.kohlmeyer/
=======================================================================
If you make something idiot-proof, the universe creates a better idiot.
(See attached file: Au_GO_PBE.psp)
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