PC GAMESS/Firefly-related discussion club

Fumihito Mohri
qzg00677@nifty.com

Recently, I started computations on organic electro-luminescence materials.
Now, I encounter the problem how to do geometry optimization for lowest-
excited- singlet sates by DFT. To my understanding, geometry optimization
for singlet-ground state (S0), lowest-excited-singlet sate (S1) and
lowest-excited triplet state (T1) can be made as follows.

In Hartree-Fock method
 S0:  $CONTRL SCFTYP=RHF  MULT=1  RUNTYP=OPTIMIZE

 S1:  $CONTRL  SCFTYP=RHF MULT=1  CITYP=CIS  RUNTYP=OPTIMIZE ...
      $CIS  MULT=1....

 T1: (a) $CONTRL  SCFTYP=RHF  MULT=1  CITYP=CIS  RUNTYP=OPTIMIZE ...
         $CIS  MULT=3....
     (b) $CONTRL  SCFTYP=UHF  MULT=3   RUNTYP=OPTIMIZE ...
      Note that (a) and (b) give different results in general.

In DFT method (ex. B3LYP)
  S0:  $CONTRL SCFTYP=RHF  MULT=1 DFTTYP=B3LYP  RUNTYP=OPTIMIZE  
       
  S1:  How to do geometry optimization ?
 
  T1:  $CONTRL  SCFTYP=UHF  MULT=3  DFTTYP=B3LYP  RUNTYP=OPTIMIZE
     
Best regatds,
Fumihito Mohri