[MMTK] NMA and mean square fluctuations

Matias Saavedra matias_saavedra at yahoo.com
Thu Aug 14 08:49:23 UTC 2008

Hi Konrad,

I would like to ask a rather basic question. 
Which is the theoretical basis for the calculation of atomic mean square fluctuations with normal modes? In particular the relation of mean square fluctuations with boltzmann constant, temperature and modes frequencies (eigenvalues). The typical relation in order to calculate B-factors. I cannot find a reference wich explain this issue with detail.

Why the calculation of the fluctuations suposes a division of the squared eigenvectors by the squared mode frequencies ?

And finally, why the criterion for the applicability of classical mechanics is hv<<KbT ? and how this affects the interpretation of NMA?

Thanks a lot!

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