[DFTB-Plus-User] R: UV-Vis Calculations and in error (NrOfExcitations)

[daniele.veclani at isof.cnr.it]

Dear Thomas,

 

first of all thanks for your reply, no my system is a protein fragment + ligand, and this system was well optimized before the UV-vis calculation. I don't understand where the metallic character can come from. However I get the same error even if I run the tutorial input (with relative geometry) found in the DTFB+ recipes (recipes_DFTB+/linresp/macromolecule).

 

And I don't understand why also the tutorial calculation crashes.

 

Do you have any suggestion?

 

Best regards,

Daniele.

 

Da: DFTB-Plus-User <dftb-plus-user-bounces at mailman.zfn.uni-bremen.de> Per conto di Thomas Niehaus
Inviato: mercoledì 15 febbraio 2023 16:56
A: dftb-plus-user at mailman.zfn.uni-bremen.de
Oggetto: Re: [DFTB-Plus-User] UV-Vis Calculations and in error (NrOfExcitations)

 

Dear Daniele,

it seems that your system is metallic. There are several fractional occupations. This means that the response matrix to diagonalize becomes gigantic and that there are clusters of near zero excitation energies which the iterative eigensolver can not separate. 

I would suggest to identify the origin of the metallic behaviour. Is the structure chemically sound?

Best regards

Thomas  

 
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