[DFTB-Plus-User] SCC unconvergence problem

[Bálint Aradi]

On 12/03/2012 09:38 PM, Vinay Hegde wrote:
> Dear Mahesh,
> 
> Please look at the trend in the total energies in the standard output.
> Does it look like it is converging (is the SCC error reducing
> systematically)? If yes, then you would do well to increase the
> MaxSCCIterations. If, instead, your structure appears to be stuck in a
> local minimum, you could try one of the following:
> 1. Use some finite temperature to speed up convergence (be aware of
> the consequences though)
> 2. Use a few non-SCC iterations initially
> 3. Use ConvergentForcesOnly = No
> The last two options being useful in case you have some non-physical
> geometries to begin with.

 Vinay excellent summarized your options. Just one more hint: If your
system is metallic or has a very small HOMO-LUMO gap, then you
definitely have to use finite temperature.

  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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