[Pw_forum] how to get Interatomic force constants

[Paolo Giannozzi]

On Monday 24 July 2006 12:16, 张睿智 wrote:

> I calculated Pb2MgTeO6, following example06. But I do not know how to get
> the IFC’s. As README in example06 tells, the IFC’s are contained in the
> Pb2MgTeO6.fc file, but in this file there are only ten matrix(see below),
> represents atom1-atom10.  How can I know the IFC between Pb-O, Te-O, 
> Mg-O, from these matrix?

you cannot: what you sent is not the file containing interatomic force
constants in real space, C(R). It looks like the file containing the dynamical
matrices, i.e. C(q) (apart from the mass factors), but it actually contains
only the dielectric tensor and the effective charges (so it should be q=0).
Are you really sure you correctly followed example 06?

Paolo
-- 
Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
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