[Pw_forum] ecutwfc convergence

[Yusuf Zuntu]

Dear Manasaje

The system is graphene with 32 carbon atoms. The cutoff is not specified in the pseudo and I need it before proceeding to other SCF and nscf calculations and believe, cutoff is a property of an atom in question. So can I still go ahead with the atoms in the unit cell. Thank you for your quick response
Yusuf


________________________________
 From: Eduardo Ariel Menendez Proupin <eariel99 at gmail.com>
To: pw_forum at pwscf.org 
Sent: Wednesday, September 26, 2012 7:18 PM
Subject: Re: [Pw_forum] ecutwfc convergence
 

Dear Yusufm 

ecutwfc and ecutrho depend only on the hardest of the pseudopotentials used for the atoms in the molecule or the crystal. If your molecule is C32 and have no other elements, you can make tests with a C2 (which does not exists, I guess), and the cutoffs for C32. 

Anyway, if your are going to calculate something that it is not the total energy or the DOS, let's say, the phonons, or the Raman spectrum, it is reasonable that you test the effect of the cutoff first on C2 and then on C32. 
---------- Mensaje reenviado ----------
From: Yusuf Zuntu <yzunt at yahoo.com>
To: PWSCF Forum <pw_forum at pwscf.org>
Cc: 
Date: Wed, 26 Sep 2012 03:15:32 -0700 (PDT)
Subject: [Pw_forum] ecutwfc convergence

Hi,
I need clarification on kinetic energy cutoff. I have a system comprising 32 carbon atoms. Am I to consider total 32 carbon atoms in  convergence w.r.t kinetic energy cutoff scf calculation or the two carbon atoms in the unit cell.
Thank you for anticipated reply.
Yusuf



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