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# Compare vibrational frequencies for two calculations for H2S- (Hydrogen sulfide anion)

### A = HF/6-31G* B = MP2/6-31G*

scale factors=0.8985, 0.943
symmetry   frequency (cm-1)   reduced mass (amu)   IR Intensity (km mol-1)
mode number A B   A B diff. ratio   A B diff. ratio   A B diff. ratio
1 A1 A1   1496 1640 -143.7 0.912   1.025 1.033 -0.008 0.992   254.01 292.64 0.868
2 A1 A1   1247 1304 -56.5 0.957   1.051 1.042 0.009 1.008   132.92 89.64 1.483
3 B2 B2   4553i 4966i 412.6 0.917   1.033 1.033 -0.000 1.000   16817.19 25333.39 0.664
scaled by     0.8985 0.943

See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.