<div dir="ltr"><div class="gmail_default" style="font-size:small">Thank you Prof. Nicola Marzari for more information.<br><br></div><div class="gmail_default" style="font-size:small">With kind regards,<br></div><div class="gmail_default" style="font-size:small">Kumar<br></div><div class="gmail_extra"><br><div class="gmail_default" style="font-size:small;display:inline">​​</div>On Fri, Jul 8, 2016 at 1:59 PM, Nicola Marzari <span dir="ltr"><<a href="mailto:nicola.marzari@epfl.ch" target="_blank">nicola.marzari@epfl.ch</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
<br>
Dear Kumar,<br>
<br>
<br>
the only reason to use finite differences would be to work with<br>
an exchange correlation functional for which linear-response is<br>
not implemented - otherwise you should use the phonon code.<br>
<br>
I quickly looked at the PHON package mentioned below, but I can't<br>
understand if it has the non-analytic terms for insulators - does<br>
anyone know?<br>
<br>
PHONOPY (<a href="http://atztogo.github.io/phonopy/(" rel="noreferrer" target="_blank">http://atztogo.github.io/phonopy/(</a> does, and it might be the<br>
most active/supported code interfaced to pwscf.<br>
<br>
                                nicola<br>
<span class=""><br>
<br>
On 08/07/2016 09:21, Lorenzo Paulatto wrote:<br>
> On Friday, July 8, 2016 9:20:27 AM CEST Sonu Kumar wrote:<br>
>> Dear QE users,<br>
>><br>
>> Can the QE calculate phonons using finite difference approach exploiting<br>
>> the symmetry of a system?<br>
><br>
> Dear Kumar,<br>
> the PHON package from Dario Alfé ca nbe interfaced with quantum espresso, it<br>
> takes a few hours to get started but it works very effectively.<br>
><br>
> <a href="http://www.homepages.ucl.ac.uk/~ucfbdxa/phon/" rel="noreferrer" target="_blank">http://www.homepages.ucl.ac.uk/~ucfbdxa/phon/</a><br>
><br>
> hth<br>
><br>
><br>
<br>
--<br>
</span>----------------------------------------------------------------------<br>
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL<br>
Director, National Centre for Competence in Research NCCR MARVEL, EPFL<br>
<a href="http://theossrv1.epfl.ch/Main/Contact" rel="noreferrer" target="_blank">http://theossrv1.epfl.ch/Main/Contact</a> <a href="http://nccr-marvel.ch/en/project" rel="noreferrer" target="_blank">http://nccr-marvel.ch/en/project</a><br>
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