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III.G.7. (XIII.B.3.) (XIII.D.5.)

Compare vibrational frequencies for two calculations for SCN- (thiocyanide anion)

A = HF/6-31G*

B = MP2FC/6-31G*

  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 Σ Σ   2192 2414 -221.8 0.908   12.773 12.868 -0.095 0.993   288.12 1.38 286.74 208.695
2 Σ Σ   679 708 -28.6 0.960   17.807 17.933 -0.126 0.993   11.82 15.17 -3.35 0.779
3 Π Π   465 417 48.1 1.115   12.766 12.778 -0.012 0.999   16.60 7.64 8.96 2.172
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.