[molpro-user] SAPT performance
tania at tiger.chem.uw.edu.pl
Tue Nov 9 18:14:40 GMT 2010
Dear Dr. Berger,
The fact that both monomers are the same is usually not important since
calculations are performed in a dimer-centered basis set, so for most
configurations of a complex there will be small differences in coefficients
between monomers resulting from utilizing ghost orbitals. Only for a couple of
very symmetric cases (e.g. if there is the center of inversion) the results
(energies, SCF vectors etc.) of one monomer could be in principle copied for
another monomer. This would require however writing a new part of the code and,
as I said, will be of a very limited value. Maybe one could use looser
thresholds for grids, DF etc., but I do not recommend this (maybe one of the
DFT-SAPT authors will answer this issue more competently). The only thing that
can be tried safely in your input is to restart KS for the second etc. distances
from vectors $ca and $cb, respectively, saved from a previous distance in your
On Sun, 7 Nov 2010, Berger Raphael wrote:
> Dear Molpro-Users,
> I try to do some SAPT calcluations on a "relatively small" symmetric dimer.
> Somehow I feel, that it runs not all too fast. I tried to use all the
> possible speed-up options which I am aware of. I wonder if there are other
> possibilities to increase the performance.
> For instance the monomer B calculation is exactly the same as the monomer A
> I would be very grateful for any hints and suggestions (input is attached).
> Best regards
> R. Berger
Dr. Tatiana Korona http://tiger.chem.uw.edu.pl/staff/tania/index.html
Quantum Chemistry Laboratory
University of Warsaw
Pasteura 1, PL-02-093 Warsaw, POLAND
`The man who makes no mistakes does not usually make anything.'
Edward John Phelps (1822-1900)
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