[DFTB-Plus-User] Dear dftb+ developer, is a multipole expansion scheme available for the charge fluctuation term ?
peter308 at gmail.com
Mon Oct 24 09:27:57 CEST 2016
Dear Mr. Bálint:
Thank you very much for your opinion, we have tested small gold clusters
already (N<20). We look forward to the multipole expansion scheme in the
new release version of dftb+, if possible. I think it might provide some
improvements over the current scheme.
2016-10-24 15:10 GMT+08:00 Bálint Aradi <aradi at uni-bremen.de>:
> Dear Peter,
> > It seems to me that since dftb+ always neglected some terms in DFT,
> > the partial charge can't never be the same with DFT. As a matter of
> > fact, some papers proposed to use a so called CM3 method to remedy
> > such differences in partial charge predicted by DFT and dftb+. I
> > would like to know that whether the two factors i listed above will
> > affect the global structures predicted by dftb+ ? Thank you
> > sinceriously.
> I think, your analysis is in general correct. As for the consequences
> for global structures: it really depends. As the repulsive is fitted
> against ab initio, you should get in many cases the right DFT-like
> structure, depsite the difference in the charges. But, as always with
> DFTB, you have to be critical and test if first for small systems.
> Best regards,
> Dr. Bálint Aradi
> Bremen Center for Computational Materials Science, University of Bremen
> DFTB-Plus-User mailing list
> DFTB-Plus-User at mailman.zfn.uni-bremen.de
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