[Pw_forum] 回复：Re: Graphene--Silicon Surface(scf not converge)

[wulilixiangguo at sina.com]

Thank you!
It really help! I have solved the problem!
----- 原始邮件 -----
发件人：Giovanni Cantele <giovanni.cantele at na.infn.it>
收件人：PWSCF Forum <pw_forum at pwscf.org>
主题：Re: [Pw_forum] Graphene--Silicon Surface(scf not converge)
日期：2010-3-5 04:55:41



> Hi everyone:

> I am doing a scf calculation for my structure. My structure has 660

> atoms(56 H,324C,280 Si). I use H terminated Si-C surface. But after 24

> hours calculation(46 steps), the scf accuracy still fluctuate from about 1

> to 100.

> Does anyone ever know this before?How to solve it?

> Thank you very much!



You can try to:

1) browse the forum, the issue has been discussed many many times, there

is not a unique answer the problem might be related to several issues



2) browse the QE wiki:

http://www.quantum-espresso.org/wiki/index.php/Frequently_Asked_Questions#Self-consistency_is_slow_or_does_not_converge_at_all



Did you check your geometry using, e.g., XCrysDen? Some times, mostly when

dealing with such a huge number of atoms, a wrong coordinate might give

atom overlap preventing the scf cycle from converging. You might also try

to tune some parameters related to the convergence of the scf cycle, like

mixing_beta.



Giovanni



-- 

Dr. Giovanni Cantele

CNR-SPIN and Dipartimento di Scienze Fisiche

Universita' di Napoli "Federico II"

Complesso Universitario di Monte S. Angelo - Ed. 6

Via Cintia, I-80126, Napoli, Italy

Phone: +39 081 676910 - Fax:   +39 081 676346

ResearcherID: http://www.researcherid.com/rid/A-1951-2009

Web page: http://people.na.infn.it/~cantele

Research Group: http://www.nanomat.unina.it

Skype contact: giocan74



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