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<div>Dear vega lew:
<BR>
Have you gone into the ./tmp directory to see the energy convergence of every image? The calculational statuses of all the images can be found there, and I guess your convergence problem may be due to the same reasons as ordinary electronic structrue calculations, which may be modified by change some parameters e.g. k-points numbers, smearing, nband. Or there may be some defects in the pseudopotential and you should better change for another one. May these be helpful.
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Best Wishes!
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Yours Sincerely
<BR>
L.F.Huang
<BR>
<BR>
</FONT><FONT color=#444444>> Date: Fri, 6 Nov 2009 11:35:39 +0800
<BR>
</FONT><FONT color=#444444>> From: vega lew
<BR>
</FONT><FONT color=#444444>> Subject: [Pw_forum] where is the end of an unconverged NEB calculation
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</FONT><FONT color=#444444>> To: PWSCF Forum
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</FONT><FONT color=#444444>> Message-ID:
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</FONT><FONT color=#444444>>
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</FONT><FONT color=#444444>> Content-Type: text/plain; charset="iso-8859-1"
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</FONT><FONT color=#444444>>
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</FONT><FONT color=#444444>> Dear all,
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</FONT><FONT color=#444444>>
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</FONT><FONT color=#444444>> During my NEB calculations, I found there are two possible situation. First,
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</FONT><FONT color=#444444>> the calculation could be converged after about 100 iterations. Second, the
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</FONT><FONT color=#444444>> calculation never converged in more than 300 iterations. And for the second
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</FONT><FONT color=#444444>> case, the energy barrier went down and down to a certain value, and then the
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</FONT><FONT color=#444444>> reported energy barrier went up gradually. For example in my resent job, the
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</FONT><FONT color=#444444>> energy barrier goes to 1.49 eV from the intial 2.99 eV in about 120
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</FONT><FONT color=#444444>> iterations. Then the energy barrier rise to 1.73 eV bit by bit in following
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</FONT><FONT color=#444444>> 40 iterations. And the calculation is still running while this value is
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</FONT><FONT color=#444444>> still going up. How could I deal with this situation? Could I take the
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</FONT><FONT color=#444444>> lowest value as the energy barrier of the reaction? How could I know whether
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</FONT><FONT color=#444444>> there will be another smaller value in the longer calculation?
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</FONT><FONT color=#444444>>
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</FONT><FONT color=#444444>> thank you for reading. Ang hints will be deeply appreciated.
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</FONT><FONT color=#444444>>
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</FONT><FONT color=#444444>> best,
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</FONT><FONT color=#444444>>
<BR>
</FONT><FONT color=#444444>> vega
<BR>
</FONT><FONT color=#444444>>
<BR>
</FONT><FONT color=#444444>> --
<BR>
</FONT><FONT color=#444444>> ==================================================================================
<BR>
</FONT><FONT color=#444444>> Vega Lew ( weijia liu)
<BR>
</FONT><FONT color=#444444>> Graduate student
<BR>
</FONT><FONT color=#444444>> State Key Laboratory of Materials-oriented Chemical Engineering
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</FONT><FONT color=#444444>> College of Chemistry and Chemical Engineering
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</FONT><FONT color=#444444>> Nanjing University of Technology, 210009, Nanjing, Jiangsu, China
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</FONT><FONT color=#444444>> ******************************************************************************************************************
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</FONT><FONT color=#444444>> Email: <A href=mailto:vegalew@gmail.com>vegalew@gmail.com</A>
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</FONT><FONT color=#444444>> Office: Room A705, Technical Innovation Building, Xinmofan Road 5#, Nanjing,
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</FONT><FONT color=#444444>> Jiangsu, China
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</FONT><FONT color=#444444>> ******************************************************************************************************************
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<BR>
------
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======================================================================
<BR>
L.F.Huang(黄良锋) ph.D candidate, DFT and phonon physics
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======================================================================
<BR>
Add: Research Laboratory for Computational Materials Sciences,
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Instutue of Solid State Physics,the Chinese Academy of Sciences,
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P.O.Box 1129, Hefei 230031, P.R.China
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Tel: 86-551-5591464-328(office)
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Fax: 86-551-5591434
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Web: <A href=http://theory.issp.ac.cn target=_blank>http://theory.issp.ac.cn</A</FONT><FONT color=#444444>> (website of our theory group)
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<A href=http://www.issp.ac.cn target=_blank>http://www.issp.ac.cn</A</FONT><FONT color=#444444>> (website of our institute)
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======================================================================
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