[DFTB-Plus-User] Failure in diagonalisation routine zhegvd

. Juita juita at uon.edu.au
Thu Dec 5 23:16:36 CET 2013

Dear Balint,

Thank you so much for your assistance.
I will try your suggestion.

Best regards,
From: DFTB-Plus-User <dftb-plus-user-bounces at dftb-plus.info> on behalf of Bálint Aradi <balint.aradi at bccms.uni-bremen.de>
Sent: 05 December 2013 16:52
To: User list for DFTB+ related questions
Subject: Re: [DFTB-Plus-User] Failure in diagonalisation routine zhegvd

Dear Juita,

On 12/05/2013 12:41 AM, . Juita wrote:
> Dear Users,
> I am the new user of DFTB+.  I tried the molecular dynamics simulations
> with the package, however, they stopped with error message "Failure in
> diagonalisation routine zhegvd, non-positive definite overlap!
> Minor      1 responsible".  The attached is the input file for the run.

If the error happens during the MD between two SCC iterations (so not
right at the beginning of a geometry step), then it is a problem with
the LAPACK-diagonalization routine we use per default. You can then try
the relatively robust instead by setting

Eigensolver = RelativelyRobust {}

in the Hamiltonian block.

If the error happens at the very beginning of a geometry step (1st SCC
cycle) then probably two atoms are too close to each other.

  Best regards,


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

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