[Pw_forum] epsilon.x

[mansourehp at gmail.com]

Dear Ferretti
I mean inter and intera smearings in inputpp of epsilon calculation not in inputscf. Do you mean I can set them similar kpt, Ecuts and smearing in scf input?
Thanks
M Pashangpour
IIAU,Tehran,Iran

Sent from my iPhone

> On 23 Nov 2016, at 19:56, Andrea Ferretti <andrea.ferretti at unimore.it> wrote:
> 
> 
> 
> Dear Pashangpour,
> 
> the idea is very similar to the usual kpt convergence 
> vs smearing parameter for a DOS calculation.
> 
> At variance with scf runs, here you are computing a spectral quantity 
> (the dielectric function as a function of the frequency), meaning that you 
> may need a (much) finer mesh of kpts.
> 
> In general, the larger the smearing, the lower the resolution of your 
> spectrum (in the simplest case you are replacing dirac's deltas with 
> gaussians), while the larger the kpt mesh that you use, the smaller the 
> smearing parameter can be...
> 
> I would follow a recipe like this:
> * set the smearing and converge the spectrum wrt kpts
> * if the accuracy of the spectrum (ie the resolution of its features) is
>   ok with you, exit(),
>   otherwise reduce the smearing parameter and iterate
> * by reducing the smearing you should expect to converge with a denser
>   mesh of kpts  (a rule of thumb could be dk * delta ~ constant, where
>   dk is the kpt grid spacing and delta the smearing parameter.. though
>   it probably depends on the system and on your requirements)
> 
> Andrea
> 
> 
>> Dear all
>> How can I find suitable value of intersmear and intrasmear in epsioln calculation via epsilon.x?
>> Thanks in advance
>> M. Pashangpour
>> PhD of physics
>> IAU,Tehran,Iran
>> 
>> Sent from my iPhone
>> _______________________________________________
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://pwscf.org/mailman/listinfo/pw_forum
> 
> -- 
> Andrea Ferretti, PhD
> S3 Center, Istituto Nanoscienze, CNR
> via Campi 213/A, 41125, Modena, Italy
> Tel: +39 059 2055322;  Skype: andrea_ferretti
> URL: http://www.nano.cnr.it
> 
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20161123/b325b102/attachment.html>