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

[. Juita]

Dear Balint,

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

Best regards,
Juita
________________________________________
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,

    Bálint


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