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Compare vibrational frequencies for two calculations for S3- (Sulfur trimer 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   521 526 -5.4 0.990   31.972 31.972 0.000 1.000   3.98 0.88 4.527
2 A1 A1   228 225 2.5 1.011   31.972 31.972 0.000 1.000   3.77 2.71 1.394
3 B2 B2   466 753 -286.6 0.619   31.972 31.972 0.000 1.000   959.81 25.72 37.312
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.