[Pw_forum] atomic displacements in phonon calculations

[Lorenzo Paulatto]

On Wednesday, March 1, 2017 11:54:01 AM CET Azadi, Sam wrote:
> Dear Experts,
> 
> I’m interested to know that how the amplitude of atomic displacements are
> defined in DFPT calculations? 

Hello, in density function perturbation theory, contrary to finite-differenes 
method, there is no atom displacement: quantum-mechanics perturbation theory 
is used.

See this reference: <http://journals.aps.org/rmp/abstract/10.1103/RevModPhys.
73.515> for details on the method how it is implemented in QE.

Tis lecture from Stefano Baroni to get a quick idea: < https://
www.dropbox.com/s/xi06fv6oz07j9du/EUSPec%202016%20%281%29.pdf?dl=0>


-- 
Dr. Lorenzo Paulatto 
IdR @ IMPMC -- CNRS & Université Paris 6
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