I'm trying to run Polarizable Continuum Model (PCM) calculations using the GAMESS(US) software. I'm not that well versed in what exactly these calculations are doing (beyond the whole, 'gas within a solvent cavity' explanation). So I will preface and say the calculations might be working and I am simply not understanding the results.
I am running a simple calculation just to start understanding PCM calculations, so I'm using this input:
! AutoGAMESS Version 1.1.8
! by Brian C. Ferrari
!
$CONTRL SCFTYP=RHF MULT=1 NPRINT=0 COORD=UNIQUE
RUNTYP=HESSIAN ICUT=12 ITOL=25 DFTTYP=B3LYP
MAXIT=200 QMTTOL=1E-7 ICHARG=0 ISPHER=1 $END
$SYSTEM MWORDS=800 MEMDDI=800 $END
$STATPT OPTTOL=1E-6 NSTEP=200 $END
$PCM SOLVNT=CH3OH $END
$FORCE METHOD=SEMINUM NVIB=2 PROJCT=.TRUE. $END
$SCF DIRSCF=.TRUE. FDIFF=.FALSE. CONV=1d-7 $END
$DFT JANS=2 $END
$BASIS GBASIS=CCT $END
$DATA
AutoGAMESS COx Energetics
Cnv 4,
C 6.0 0.0000000000 0.0000000000 0.5267400687
O 8.0 0.0000000000 0.0000000000 -0.5996000687
$END
The calculation terminates normally but the results it prints out are the following:
MODE FREQ(CM**-1) SYMMETRY RED. MASS IR INTENS.
1 0.000 A 12.000000 0.001636
2 0.000 A 12.000000 0.001636
3 0.000 A 12.000000 1.444876
4 0.000 A 15.994910 0.001228
5 0.000 A 15.994910 0.001227
6 0.000 A 15.994910 1.084002
This seems like garbage to me, since the frequencies are all 0 but there are some IR intensities. Which leaves me wondering what is going wrong to cause this error in the calculation? What should I change in the input file?
projct=.True.
, it should project all the translations and rotations to have zero frequency. However, that should only account for the first five in this case, so one of the options used must be making GAMESS project the bottom 6, which is the typical case for nonlinear molecules, rather than correctly zeroing out the first 5 $\endgroup$ – Tyberius Jan 2 '20 at 2:30has not reached a stationary point
however for the non-PCM calculation with the same parameters it does reach a stationary point. I'll try putting stricter convergence criteria on it and see if that helps. $\endgroup$ – Cavenfish Jan 3 '20 at 20:05