[DFTB-Plus-User] Failure in diagonalization routine

[Jacek Jakowski]

.. your problem might be related to mixing and matching different  sets of
Slater-Koster parameters.
Jacek


On Thu, Mar 26, 2015 at 2:56 PM, Jacek Jakowski <jjakowski at gmail.com> wrote:

> You should print the overlap matrix to the file. Then read in the overlap
> matrix  to   matlab,  octave or something like.   Then you should
> diagonalize  your  overlap. You should see  all the eigenvalues to be
> positive and close to 1. If you see  something  very close to zero  the you
> have a linear dependence in your basis set.  If you see something
> negative,   then   you clerarly have your reason  for cholelsky failing.
> You  can  then inspect  the corresponding eigenvectors.
>
> Jacek
>
> On Thu, Mar 26, 2015 at 6:35 AM, Yusupov Maksudbek <
> maksudbek.yusupov at uantwerpen.be> wrote:
>
>>  Dear Dr. Balint,
>>
>> I am a new user of DFTB. My system consists of biomolecule, such as
>> peptide and I want to study the interaction of OH radicals with this
>> biomolecule.
>> The peptide is located at the center of the periodic box. The box is big
>> enough, i.e., minimum image criterion was taken into account. Ten OH
>> radicals are randomly positioned around the structure (with minimum 5 A
>> distance from the structure and from each other).
>> When I run the simulation I have this error “Failure in diagonalization
>> routine dsygvd, non-positive definite overlap! Minor 107 responsible” after
>> several steps.
>> I have checked this orbital (i.e, 107) and the atom is not unphysically
>> close to other atoms.
>> Please find the dftb_in.hsd and detailed.out files in the attachment and
>> please help me to solve this problem.
>> I appreciate your time and response in advance.
>>
>> Kind regards,
>> Maksud.
>>
>>
>>  **************************************************
>> dr. Maksudbek Yusupov
>> Department of Chemistry, Research group PLASMANT
>> University of Antwerp
>> Universiteitsplein 1
>> BE-2610 Wilrijk-Antwerp, Belgium
>> Tel: +32 3 265 23 82
>> Fax: +32 3 265 23 43
>> E-mail: *maksudbek.yusupov at uantwerpen.be
>> <maksudbek.yusupov at uantwerpen.be>*
>> Website: *https://www.uantwerp.be/en/rg/plasmant/
>> <https://www.uantwerp.be/en/rg/plasmant/>*
>> **************************************************
>>
>>
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>>
>>
>
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