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

[Thomas Niehaus]

Dear Daniele,

On 2/16/23 9:58 AM, daniele.veclani at isof.cnr.it wrote:
>
> Dear Thomas,
>
> “when you say the system was well optimized, did you check the state 
> occupations at the final structure (-> band.out)?”
>
> Yes, I check the state occupations at the final structure (band.out) 
> and no fractional occupations was observed.
>
> I report below a fragment of the band.out file corresponding to the 
> HOMO-LUMO gap:
>
> “  1884    -4.784  2.00000
>
>   1885    -4.677  2.00000
>
>   1886    -4.581  2.00000
>
>   1887    -4.314  2.00000
>
>   1888    -2.723  0.00000
>
>   1889    -2.124  0.00000
>
>   1890    -1.949  0.00000”
>
Can you please send the geometry and input file for this job?
>
> Is your system zwitterionic, are the ligands maybe charged....
>
> Yes, protein have a charge of +4 while ligand have a -1 charge (total 
> charge +3). I have to respect these charges because I have to study 
> the system at a given pH.
>
Sure, but why do you set 'Charge = -3' if the total charge is +3?
>
> Did you run the tutorial with the geometry and input file for that 
> tutorial?
>
> Yes, I ran the geometry and input file found in 
> recipes_DFTB+/linresp/macromolecule, however I obtain then same error.
>
> I use a 21.2 version of DFTB+ software.
>
I can not reproduce this. For me the recipes_DFTB+/linresp/macromolecule 
job runs smooth with dftb+ 22.2 (I don't expect dftb+21.2 to be any 
different).

Best Thomas

> Best,
>
> 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 17:27
> *A:* dftb-plus-user at mailman.zfn.uni-bremen.de
> *Oggetto:* Re: [DFTB-Plus-User] R: UV-Vis Calculations and in error 
> (NrOfExcitations)
>
> Dear Daniele,
>
> when you say the system was well optimized, did you check the state 
> occupations at the final structure (-> band.out)? Is your system 
> zwitterionic, are the ligands maybe charged....
>
> Did you run the tutorial with the geometry and input file for that 
> tutorial? I don't understand what you mean with relative geometry.
>
> Best Thomas
>
> On 2/15/23 5:03 PM, daniele.veclani at isof.cnr.it 
> <mailto:daniele.veclani at isof.cnr.it> wrote:
>
>     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>
>     <mailto: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
>     <mailto: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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>
> -- 
> Prof. Dr. Thomas Niehaus
> Institut Lumière Matière
> UMR5306 CNRS
> Université Claude Bernard Lyon 1
> Domaine Scientifique de La Doua
> 10 rue Ada Byron
> 69622 Villeurbanne CEDEX, France
> --
> Office: Brillouin building, 4th floor, room 006
> Tel: +33 472 431 571
> Home page:http://ilm-perso.univ-lyon1.fr/~tniehaus  <http://ilm-perso.univ-lyon1.fr/~tniehaus>
> Lab:http://ilm.univ-lyon1.fr  <http://ilm.univ-lyon1.fr>
>   
>
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-- 
Prof. Dr. Thomas Niehaus
Institut Lumière Matière
UMR5306 CNRS
Université Claude Bernard Lyon 1
Domaine Scientifique de La Doua
10 rue Ada Byron
69622 Villeurbanne CEDEX, France
--
Office: Brillouin building, 4th floor, room 006
Tel: +33 472 431 571
Home page: http://ilm-perso.univ-lyon1.fr/~tniehaus
Lab: http://ilm.univ-lyon1.fr
  

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