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Re: About MCSCF Frequency

sanya
sanya@photonics.ru


Don't worry, it's OK. This warning means that the program takes the frequencis starting from #7 as vibrational in the calculation of thermodynamic functions, even if one or more frequencies are imaginary.
Anyway, you have to check the output for the presence of imaginary frequencies. In your output, it's OK, no imaginary frequencies. Just in case, check the modes with any molecular viewer to see that the first 6 modes are really TRANSLATION/ROTATION.

On Tue Dec 18 '12 8:10am, Panwang Zhou wrote
--------------------------------------------
>Dear all,

>Recently I optimized some molecules with MCSCF and do the frequency calculation after the optimization. In some of the output files I found the following warning information:

> * * * WARNING, MODE 7 HAS BEEN CHOSEN AS A VIBRATION
>          WHILE MODE 1 IS ASSUMED TO BE A TRANSLATION/ROTATION.
> PLEASE VERIFY THE PROGRAM'S DECISION MANUALLY!
>
>
> MODES 1 TO 6 ARE TAKEN AS ROTATIONS AND TRANSLATIONS.

>     FREQUENCIES IN CM**-1, IR INTENSITIES IN DEBYE**2/AMU-ANGSTROM**2

>                          1           2           3           4           5
>       FREQUENCY:        37.38       11.03        4.32        1.41        0.83  
>    REDUCED MASS:      4.04148     5.98182     6.38515     8.15107     8.04677
>    IR INTENSITY:      0.00767     0.02150     0.02270     0.12653     0.14352

>                          6           7           8           9          10
>       FREQUENCY:         3.07       32.50       42.75       55.57       82.43  
>    REDUCED MASS:      8.43095     2.01865     3.23463     2.39530     5.49036
>    IR INTENSITY:      0.13750     0.01437     0.02990     0.00877     0.04674

>So, what's the meaning of this warning? Is it necessary to eliminate this warning and how to do? Thanks.

>Following is my input file:
>$CONTRL SCFTYP=MCSCF RUNTYP=OPTIMIZE EXETYP=RUN MAXIT=50 ICHARG=-1
>    MULT=1 FSTINT=.T. GENCON=.T. D5=.T. INTTYP=HONDO NOSYM=1
>    ICUT=11 ITOL=30 $END
> $SYSTEM MWORDS=300 TIMLIM=60000.0 KDIAG=0 NOJAC=100 $END
> $SCF DIRSCF=.T. FDIFF=.F. NCONV=8 $END
> $P2P P2P=.T. DLB=.T. $END
> $TRANS MPTRAN=2 DIRTRF=.T. AOINTS=DIST ALTPAR=.T. MODE=112 $END
> $MCSCF CISTEP=ALDET FULLNR=.F. SOSCF=.T. $END
> $DET NCORE=49 NACT=14 NELS=16 $END
> $BASIS EXTFIL=.T. GBASIS=TZVP $END
> $GUESS GUESS=MOREAD NORB=642 NORDER=1
>   IORDER(40)=50 IORDER(50)=40 IORDER(45)=52 IORDER(52)=45
>   IORDER(63)=64 IORDER(64)=63 $END
> $STATPT NSTEP=200 METHOD=GDIIS OPTTOL=0.00001 HSSEND=.T. $END
> $FORCE NVIB=2 $END


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