[DFTB-Plus-User] "Failure in diagonalisation routine dsygvd.." error

Jan M. Knaup Jan.Knaup at bccms.uni-bremen.de
Wed Jul 10 16:25:22 CEST 2013

Dear Vinay,

your problem is most probably caused by two atoms coming too close to each
other. The problem ist connected to the 1091st orbital in the system. You
can find out which atom it belongs to by counting the orbitals of the atoms
in your geometry ("s" atoms have 1 orbital, "p" atoms ave 4 and "d" atoms
have 9).

Changing miximg parameters or other parameters of the electronic
calculation is not likely to help, because the converged electronic
structure should always be the same. I suggest that you carefully check the
last output geometry that is written by the program, it should give you
some hint at what is going wrong with your calculations.


Jan M. Knaup                      | Fon +49-(0)421-218-62351
Dipl. Phys. Dr. rer. nat.         | Fax +49-(0)421-218-62770
Universität Bremen - BCCMS        |
Am Fallturm 1                     | Jan.Knaup at bccms.uni-bremen.de
28359 Bremen                      | JanKnaup at gmail.com
Germany                           | www.bccms.uni-bremen.de

2013/7/9 Vinay Hegde <hegdevinayi at gmail.com>

> Dear users and developers,
> I am studying N_2 and CO_2 adsorption properties in a MOF using the
> 'znorg-0-1' parameter set. All bulk calculations ran fine but I am
> facing a strange error when performing constrained geometry
> optimization for the (001) surface with ~20 Angstrom of vacuum.
> Interestingly, in all the different configurations (I have 12-15
> different configurations of the molecule on the MOF), this error
> occurs exactly (this is the only reason I called it a strange error)
> at the 31st geometry step:
>  ********************************************************************************
>  ** Geometry step: 31
>  ********************************************************************************
>    iSCC Total electronic   Diff electronic      SCC error
>  -> Failure in diagonalisation routine dsygvd, non-positive definite
> overlap! Minor   1091 responsible.
> I have tried changing the mixing parameter, the mixer itself,
> distorting the location of atoms a little and so on but the error
> keeps occurring there: at the 31st geometry step.
> I have attached my dftb_in.hsd file and the standard output with this
> mail. I am using DFTB+ 1.2 and the precompiled binary for my
> calculations.
> Any suggestions or pointers are most welcome.
> Regards,
> Vinay
> --
> Vinay Ishwar Hegde
> Graduate Student
> Theoretical Sciences Unit (TSU)
> Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR)
> Jakkur, Bangalore 560 064
> Email: vinayhegde at jncasr.ac.in
> Phone: +91-96639-92336
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> DFTB-Plus-User at dftb-plus.info
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