[CPMD-list] Pseudopotentials and diferences in results

[Jim Kress]

Dear Dr. Hutter,

Thank you for your reply.

Should I also be using Kleinman-Bylander with the Goedecker
pseudopotentials?

Thanks for your help.

Jim


----- Original Message ----- 
From: "Juerg Hutter" <hutter at pci.unizh.ch>
To: "Jim Kress" <cpmd at kressworks.com>
Cc: <cpmd-list at cpmd.org>
Sent: Tuesday, April 06, 2004 3:12 AM
Subject: Re: [CPMD-list] Pseudopotentials and diferences in results


> Dear Jim
>
> the problem is related to your input using MT pseudos
> You probably want to use the Kleinman-Bylander form of
> these pseudopotentials. However, not specifying anything
> defaults in the current version to a Gauss-Hermite
> integration using 0 points -> neglect of non-local part.
>
> I suggest you use
> *C_MT_BLYP_2 Kleinman-Bylander
>  LMAX=P
>
> for all elements with LMAX > S.
> To get good numerical results you should also increase
> the cutoff. 70-85 Ry for TM pseudos and 80-120 Ry
> for the Goedecker pseudos.
>
> regards
>
> Juerg Hutter
>
>
> ----------------------------------------------------------
> Juerg Hutter                   Phone : ++41 1 635 4491
> Physical Chemistry Institute   FAX   : ++41 1 635 6838
> University of Zurich           E-mail: hutter at pci.unizh.ch
> Winterthurerstrasse 190
> CH-8057 Zurich, Switzerland
> ----------------------------------------------------------
>
>
> On Mon, 5 Apr 2004, Jim Kress wrote:
>
> > I'm using CPMD v3.7.2 on a small Linux cluster and am a novice in the
> > application of the CPMD code.   I am a Computational Chemist by
education
> > and experience with quite a bit of experience working with pcGAMESS and
> > similar Quantum Chemistry codes.
> >
> > To familiarize myself with the CPMD code and its applications I have
been
> > performing some single molecule calculations.  I recently tried some
> > calculations where I used different pseudopotentials.  I got some rather
(to
> > me) strange looking results, i.e., for my molecule of interest (using
the
> > Goedecker pseudopotentials distributed with CPMD) I calculated a total
> > energy of -54.265019 au.  However, using exactly the same input file but
> > specifying the Trouiller-Martins pseudopotentials (also distributed with
> > CPMD) I calculate a total energy of -85.349239 au.
> >
> > Is this to be expected or do I have a whopper of an error in my input?
> >
> > I've attached in input and output files for inspection.
> >
> > Any comments, suggestions, or explanations of why these results are
observed
> > would be greatly appreciated.
> >
> >
> > Jim
> >
>