[Wien] mBJ potential for molecules?

[Ricardo Faccio]

Dear users

I've been working on the isolated molecule catechol (http://en.wikipedia.org/wiki/Catechol) in order to see how mBJ affects its HOMO-LUMO gap.

The initialization and convergence at GGA-PBE level went fine, obtaining a energy gap of 4.0 eV in concordance with other DFT codes.

Afther this I proceeded in order to incorporate the modified Becke-Johnson potential (MBJ), but I found several problems in determining the position of the Fermi level. What we see is a clear problem of finding enough eigenvalues, which arelower than the number of valence electrons. Therefore we proceed according to the userguide by:
-changing the Fermi-Method (tetra, gauss and temp) -> error persist
- changing Rmt to similar values increasing the lmax to12 -> error persist
- increasing energy window in case.klist  and case.in1c in order to catch the lost eigenvalues -> error persist
It seems to be a problem on a big change introduced by the mBJ potential which induces important divergences iat the  lapw1. 

######################

case.output1up 

###################### 

    EIGENVALUES ARE:
      1.4443359    1.4892578    1.8037109    1.8486328    1.8486328
      1.8935547    1.9384766    1.9384766
         1923 EIGENVALUES BELOW THE ENERGY   -9.00000
       ********************************************************
The problem always occurs in the first cycle of the mBJ procedure after lapw1, with few eigenvalues as you can see.

I succeed applying this methodology to bulk systems such as TiO2.

Any suggestion?

Best regards

Ricardo

 

-------------------------------------------------------------------------
  Dr. Ricardo Faccio
  Prof. Adjunto de Física 
  Mail: Cryssmat-Lab., Cátedra de Física, DETEMA
  Facultad de Química, Universidad de la República
       Av. Gral. Flores 2124, C.C. 1157
       C.P. 11800, Montevideo, Uruguay.
  E-mail: rfaccio at fq.edu.uy
  Phone: 598 2 924 98 59
              598 2 929 06 48
  Fax:    598 2 9241906
  Web:  http://cryssmat.fq.edu.uy/ricardo/ricardo.htm
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