[Pw_forum] frequency of NO molecule
giannozz at nest.sns.it
Thu Sep 7 17:31:34 CEST 2006
On Thursday 07 September 2006 16:01, Axel Kohlmeyer wrote:
> how about including several atoms in the neighborhood of the
> adsorbed molecule? this is how it works in CPMD: you pick an
> atom (or pick a reference coordinate) and set a radius and then
> do the vibrational analysis for those atoms and keep the rest fixed.
> this way you include at least the contributions from the near
> neighbors, have the rest as 'static background', and still save
> a lot of (cpu) time.
the problem I see in this approach is that the vibrations of
surface atoms close to the adsorbed molecule may be
strongly correlated to vibrations of other atoms in the
surface; i.e., taking only a few surface atoms close to
the molecule will produce rather bogus displacement
patterns for those atoms.
Paolo Giannozzi Phone: +39/050-509876
DEMOCRITOS and SNS Fax: +39/050-563513
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