[Pw_forum] About pseudopotential

[Axel Kohlmeyer]

On Mon, Aug 20, 2012 at 2:05 PM, anne etindele <annetindele at yahoo.fr> wrote:
> Dear  all
>
> I am interested on the determination of the total energy of C60.
> I have used the pseudopotential I found in the "pseudopotential" folder of
> Quantum espresso.
> I realised that the value of total energy of atoms obtained with pw.x is
> different from the one with ld1.x for the atom itself. finally the total
> energy of C60 is
> really far from the the value obtained with quantum chemistry code like
> Gaussian.
>
> I would like to know if there is a way to get the real total energy of
> systems
> when we use pseudopotential?

no. the total energy is a useless property,
even with when doing all-electron calculations
with gaussian. the only meaningful properties
are energy *differences*.

even gaussian doesn't compute the *real*
total energy; it completely neglects the energy
that holds the atom cores together (or the
individual nucleons for that matter).

cheers,
    axel.


>
> Anne Justine ETINDELE
> PhD Student,
>
> University of Douala ( CAMEROON)
> Descente Mont Essec
> P.O. Box 24157 Douala
> Cameroon
>
>
>
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-- 
Dr. Axel Kohlmeyer  akohlmey at gmail.com  http://goo.gl/1wk0
International Centre for Theoretical Physics, Trieste. Italy.