[DFTB-Plus-User] question about DFPB+ Failure of routine zheqvd

[Bálint Aradi]

Dear Zhenyuan Shen,

> I'm a junior student from HUST in China .I have just started using MS and
> DFTB+ doing some research on the graphene nano-ribbon ,and got the error
> below while using the trans3d set for calculating the energy band of
> graphene nano-ribbon.
> *-> Failure in diagonalisation routine zhegvd, non-positive definite
> overlap!**Minor  ...  responsible*
> **
> **
> *My input file "dftb_in.hsd" is as follows*
> 
>   Geometry = GenFormat {
> 28 S
> C
> 1 1 0.27643   0.00324   0.50900


  your atoms are too close to each other. Then the overlap matrix will
be positive non-definite due to basis superposition error.

  Best regards,

  Bálint

Ps. Please direct any further queries about the usage of DFTB+ to the
DFTB-Plus-User mailing list. I cc-d this answer there as well.

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


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