[DFTB-Plus-User] Molecular Dynamics ERROR

Bálint Aradi balint.aradi at bccms.uni-bremen.de
Wed Dec 2 11:22:54 CET 2009

Dear Mandelle Danser,

Mandelle Danser wrote:
> I am trying to run molecular dynamics simulations and within the run an
> error message comes up saying 'failure in diagonalisation routine dsygvd,
> non-positive definite overlap!'  Is there any way to get around this?  What
> must be changed in the input to avoid such errors?
> Thank you.

 This usually happens, if your MD simulation results in a strange
geometry, where you encounter basis superposition error. The
straightforward way to work around it would be either to use the
Standard Lapack diagonalizer, instead of divide and conquer, as latter
is less picky about the overlap matrix. If even that one fails, you
should modify the geometry a little bit, and start again.

  Best regards


Dr. Bálint Aradi
Bremen Center for Computational Materials Science, University of Bremen

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