Molcas Forum

karney

Member

From: University of San Francisco

Registered: 2018-09-07

Posts: 4

Website

Oscillator strengths in RASSI with solvent

Hello,
I get strange results for oscillator strengths (but also energies) when trying to obtain excited state info with solvation. For acrolein as a model, I'm using the following input, which is mostly from page 68 of the Molcas 8.2 manual, but I'm extending it by including the RASSI module:

&GATEWAY
  Title= Acrolein excited state with solvation
  Coord=$MOLCAS/Coord/Acrolein.xyz; Basis= STO-3G; group= c1
  RF-input
    PCM-model; solvent= water
  End of RF-input
  End of Input
&SEWARD
&SCF
&RASSCF
  Spin= 1; nActEl= 6 0 0; Inactive= 12; Ras2= 5
  CiRoot= 1 1 1
  End of Input
&CASPT2
  Multistate= 1 1
  RFPert
  >> copy $Project.JobMix JOB001
  End of Input
&RASSCF
  Spin= 1; nActEl= 6 0 0; Inactive= 12; Ras2= 5
  CiRoot= 5 5 1
  RFRoot= 5
  NONEquilibrium
  End of Input
&CASPT2
  Multistate= 1 5
  RFPert
  >> copy $Project.JobMix JOB002
  End of Input
&RASSI
  NRofJOBiph= 2 1 1; 1; 5
  EJob
  RFPert
  End of Input

The RASSI module output that confuses me is:

SF State    Relative EVAC(au)   Rel lowest level(eV)      D:o, cm**(-1)

     1            -193.16016810            0.000000               0.000
     2           52000.00000000      1420248.228938     11455074587.940

and

++ Dipole transition strengths:
   ----------------------------
    for osc. strength at least   0.10000000E-04

         To  From     Osc. strength   Einstein coefficients Ax, Ay, Az (sec-1)       Total A (sec-1)
         -------------------------------------------------------------------------------------------
         1    2        29098.452      0.25284467E+25  0.18421329E+23  0.46384610E+17  0.25468680E+25
         -------------------------------------------------------------------------------------------

The relative energies of the states reported by RASSI seem nonsensical, and the oscillator strength seems extremely large. Am I doing this correctly?
Thanks,
William Karney

---

William Karney
Prof. of Chemistry and Environmental Science
University of San Francisco

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,203

Re: Oscillator strengths in RASSI with solvent

My personal conviction is that RASSI should simply not be used with jobiphs coming from different solvent calculations. Different solvent settings mean a different reaction field an a different Hamiltonian, but RASSI can only handle a single Hamiltonian, so the results are bound to be wrong.