[Pw_forum] Total energy convergence

[Eyvaz Isaev]

Hi, 


----- Original Message ----
From: mayank gupta <mayankaditya at gmail.com> 

> I am interested in phonon calculation. I want to know for phonon
> calculation  what is the order of total energy convergence  and k mesh
> size should be taken in scf  calculation? Should I take larger value
> than the band calculation parameters.

First, you can use the convergence criteria used in example06  (10^{-8} for scf 
and 10^{-12} for ph), then decide you are satisfied or not. 


As concerns k-points, just keep in mind phonon calculations are time consumable, 
so, more k-points, more time is required. So, the best choice is "trial and 
fail". That means you are responsible for your own choice and results.  


Bests,
Eyvaz.
-------------------------------------------------------------------
Prof. Eyvaz Isaev, 
Department of Physics, Chemistry, and Biology (IFM), Linkoping University, 
Sweden 

Theoretical Physics Department, Moscow State Institute of Steel & Alloys, 
Russia, 

isaev at ifm.liu.se, eyvaz_isaev at yahoo.com