If you mean counterpoise corrected geometry optimisation, that's tricky, and
definitely not implemented in SIESTA. Counterpoise is only really
straight-forward for dimers (or at least small numbers) of fairly rigid
molecules. In a crystal, you would have to make sure that your supercell is big
enough (you can't CP correct the interaction of a molecule with its image), and
I don't know the implications for K-points (my first inclination would be to say
if you need more than one K-point, your system is too dense for counterpoise to
be meaningful).
Have you tried adding diffuse functions? BSSE is a consequence of the
incompleteness of localised basis sets. If you describe the wavefunction far
away from the nuclei better, it should improve, but I don't know how quickly.
HTH,
Herbert
Gregorio García Moreno wrote:
Hi all
I am studing polymers pi-stacked. I have obtained good crystal
parameters, except for the pi-stacking distance, which is smaller than
experimental data. Here, you recomended me that I should use TZP and
BBSE. I have tried with TZP, but the results do not improve respect to
DZP. However, I have searched in literature, and to apply BSSE could
solucionate my problem.
In the SIESA-list I have not found how to optimize with BSE, can someone
help me?
Thanks in advance
Gregorio
--
Herbert Fruchtl
Senior Scientific Computing Officer
School of Chemistry, School of Mathematics and Statistics
University of St Andrews
--
The University of St Andrews is a charity registered in Scotland:
No SC013532
