[DFTB-Plus-User] MD in dftb+ (SCC=Yes/No?)

Bálint Aradi balint.aradi at bccms.uni-bremen.de
Mon Dec 17 12:51:31 CET 2012


Dear 刘雷,

On 12/17/2012 03:18 AM, 刘雷 wrote:
> Dear all,
> I did a test about "SCC=Yes" or "SCC=No" when I try to do MD simulation in dftb+,the simulation speed of "SCC=No"  is ten times of the speed of "SCC=Yes".
> Previously,I have noticed there was someone who used "SCC=No" when he did MD simulation.In my opinion,we shoule use "SCC=Yes" though its slow simulation speed.
> Am I right? If not,I want to know the explanation.

 Of course non-scc is faster, as you do not make any self consistency
loop for the charges. In general, you should use SCC = Yes, especially
if you are using SK-sets which were made for SCC calculations.

  You may get away to make a *few* non-scc steps, if SCC does not
converge for your geometry. Non-scc could be also an option, if you have
a homonuclear system without any significant charge transfer between the
atoms (e.g. carbon nanotubes, fullerenes). But apart of those special
cases, the general advice is to use SCC, as otherwise your forces and
consequently your MD-trajectory could be wrong.

  Best regards,

  Bálint


-- 
Dr. Bálint Aradi
Bremen Center for Computational Materials Science, University of Bremen
http://www.bccms.uni-bremen.de/cms/people/b_aradi/


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