[CP2K-user] [CP2K:12007] Problems computing LUMO energy for a non-periodic metallic cluster using PM6

[hut... at chem.uzh.ch]

Hi

you need "ADDED_MOS 100" in the &SCF section. Together with an
optimiser with diagonalization (default) and the section

&PRINT
  &MO
     EIGENVALUES
  &END
&END

you will get the HOMO-LUMO value.

regards

Juerg
--------------------------------------------------------------
Juerg Hutter                         Phone : ++41 44 635 4491
Institut für Chemie C                FAX   : ++41 44 635 6838
Universität Zürich                   E-mail: hut... at chem.uzh.ch
Winterthurerstrasse 190
CH-8057 Zürich, Switzerland
---------------------------------------------------------------

-----cp... at googlegroups.com wrote: -----
To: "cp2k" <cp... at googlegroups.com>
From: "Matt W" 
Sent by: cp... at googlegroups.com
Date: 07/29/2019 08:53PM
Subject: Re: [CP2K:12007] Problems computing LUMO energy for a non-periodic metallic cluster using PM6

Try using the MO section rather than MO_CUBES...it may not work.

The semi-empirical methods do not have the full functionality of the DFT methods. I'd suggest trying DFT (for very small systems, but then you know the input works), then seeing if you can do it with PM6 or similar.

Matt

On Monday, July 29, 2019 at 6:03:31 PM UTC+1, Richard Marchese Robinson wrote:      
 
 Hi Patrick,
  
 Thanks for the suggestion, but this does not solve the problem.
  
 Best regards,
  
 Richard
  
 From: c... at googlegroups.com [mailto:c... at googlegroups.com] On Behalf Of Patrick Gono
 Sent: 29 July 2019 17:47
 To: c... at googlegroups.com
 Subject: Re: [CP2K:12004] Problems computing LUMO energy for a non-periodic metallic cluster using PM6
  
 
 
 Dear Richard,
  
  
  
 Try to switch off the printing of the cube files, while maintaining NHOMO and NLUMO equal to 1 in the PRINT section of DFT:
  
 &DFT
  
 ...
  
     &PRINT
         &MO_CUBES
             NHOMO  1
             NLUMO  1
  
             WRITE_CUBE .FALSE.
  
         &END MO_CUBES
     &END PRINT
 &END DFT
  
  
  
 Does it help?
  
  
  
 Yours sincerely,
  
 Patrick Gono
    
 
 
 On Mon, 29 Jul 2019 at 18:25, Richard Marchese Robinson <r.l... at leeds.ac.uk> wrote:
   
 Dear all,
  
 Firstly, thanks to the developers for making this tool available to the community.
  
 I have only recently started using CP2K and I am hoping to be able to compute HOMO – LUMO gaps and individual energies for non-periodic, metallic clusters using different levels  of theory. (It is my understanding from the literature that this gap should tend to zero as the clusters become larger.)
  
 I am trying to perfom this calculation at the PM6 level of theory. 
  
 I provide my input and output files. 
  
 It is my understanding that the 22 eigenvalues in the output files refer to the energy levels of the occupied valence orbitals, with the Fermi energy corresponding to the energy  of the HOMO.
  
 However, as far as I can tell, I cannot obtain the LUMO energy. Am I overlooking something?
  
 I have tried to address this using both the MO and MO_CUBES settings in the input files. I get a warning about the printing of MO cube files not being implemented for semi-empirical  methods, e.g. PM6. Since this section is the only section which explicitly refers to the LUMO in the input file, does this mean PM6 LUMO values cannot be computed using CP2K?
  
 I am running cp2k.7.0.190717.for.winxp.fftw3 on Windows 7.
  
 Thanks in advance for any assistance you have time to provide.
  
 Best regards,
  
 Richard
  
 ----- 
 Dr Richard Marchese Robinson
 Post-Doctoral Research Associate
 BioRima Project [https://www.biorima.eu/]
 University of Leeds
 United Kingdom
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