[Pw_forum] frequency of NO molecule

Paolo Giannozzi giannozz at nest.sns.it
Thu Sep 7 09:34:18 CEST 2006

On Wednesday 06 September 2006 21:12, Hong, SamPyo wrote:

> As I looked into the code, I found that that can be done very easily.
> [...]
>  nat_todo=2, <== Here we specify number of atoms to be displaced.
>  /
>  0.0 0.0 0.0
>  31 32 <== Here we specify atom index in our supercell.
> That's it. Later I found that INPUT_PH has a mention regarding this.

in this way you just calculate and diagonalize the 6 x 6 submatrix of the
dynamical matrix. 

In principle it should be possible to reconstruct an approximate dynamical
matrix from the above calculation and the dynamical matrix of the surface
without NO. I don't know how useful this would be, though.

> I wish that this procedure could be explained very clearly in the manual
> in coming version.

it is not clearly explained right now because it is a seldom-used feature
(and one that should be carefully used). If you have any specific suggestions
to improve the manual, feel free to suggest them

Paolo Giannozzi             Phone:   +39/050-509876
DEMOCRITOS and SNS          Fax:     +39/050-563513 
Piazza dei Cavalieri 7      I-56126 Pisa, Italy

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