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

Vinay Hegde hegdevinayi at gmail.com
Tue Jul 9 13:15:13 CEST 2013

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

Any suggestions or pointers are most welcome.



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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