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[spizzinato@icp.csic.es]

Dear Yajie Lei,

if you are using the tsmear default value, you could try to put a lower value of tsmear.

The default value is quite high (0.04) and maybe the broadening of occupation of your bands corresponds to too high temperatures.

I tried to use a 0.0009 tsmear value in my calculations (cause I had the same problem but with a small cell) and the calculations reached convergence.

I hope this commentary would be usefull for you.






Date sent:      	Mon, 11 Apr 2005 19:14:19 +0200
To:             	forum@abinit.org
From:           	yajielei@gwu.edu
Send reply to:  	forum@abinit.org
Subject:        	[abinit-forum] The question about calculation of large supercell 

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Dear ABINIT users,

Could I ask you a question about the calculation of upercell
in ABINIT?

Now I am doing some calculation for Bi4Ti3O12(BIT) materials.
I tried it with nband=250. I think that is large enough. After
costing a very long time, however, I still got the information
as following

scfcge : ERROR -
Potential-based CG line minimization not converged
after 13 restarts.
Action : read the eventual warnings about lack of
convergence.
Some might be relevant. Otherwise, raise nband.

Could you give me any suggestion or any experience
about the related variable setting for such a large
supercell calculation. Looking forward to your kind
reply.

Most appreciate.

Sincerely
Yajie Lei

Department of Mechanical and Aerospace Engineering
School of Engineering and Applied Science
George Washington University
Email: yajielei@gwu.edu
Sara Pizzinato
Instituto de Catálisis y Petroleoquímica - CSIC c/ Marie Curie, 2 Campus de Cantoblanco. 28049 - MADRID Tel: 34-91-5854800 Fax: 34-91-5854760