[Pw_forum] Total Energy doesn't converge upon increase in Ecutwfc

[Ali KACHMAR]

Hi,

You did not say:

1) what QE version are you using?

2) from where did you get your Ga pseudopotential?


BTW, did you try to do the calculation with mixing beta equal  to 0.5 


PS: The v.5.0.2 (svn rev. 9783) doesn't show any convergence issue for your system.

Best,
Ali

Date: Wed, 6 Mar 2013 10:56:07 -0800
From: hanchueh at ucla.edu
To: pw_forum at pwscf.org
Subject: [Pw_forum] Total Energy doesn't converge upon increase in Ecutwfc

Dear all,
It is my understanding that as one increases the cutoff energy for the wavefunctions, Ecutwfc, the total energy of a given structure should converge towards a minimum. However, when I did this in the case with GaN with GGA, it did not seem to converge and kept dropping energy more as I increased the Ecutwfc. Why is this happening? I will include a sample input file and Excel file showing this behavior.


>From the Excel graph, one can see that the total energy appears to converge between 50 Ry and 70 Ry but then began to drop rapidly after that. It appeared to converge again between 100 and 200 Ry but again dropped down rapidly after that.


Sincerely,

Han Chueh

_______________________________________________
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/20130306/a882a394/attachment.html>