[Pw_forum] phonon & temperature

[Paolo Giannozzi]

On Nov 15, 2009, at 5:40 , Mehrnaz Anvari wrote:

> In addition the  source of these displacements in crystals is  
> temperature,
> and it sometimes causes that crystal doesn't  have smooth surface for
> example in room temperature. now, I want to know that can I say that
> the calculations consist of this surface flactuations?

you cannot say anything about surfaces in a bulk crystal with periodic
boundary conditions: there is no surface

P.
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Paolo Giannozzi, Dept of Physics, University of Udine
via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222