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

Compare vibrational frequencies for two calculations for HCN- (Hydrogen cyanide 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 A' A'   1800 2319 -519.4 0.776   1.396 6.637 -5.241 0.210   463.84 615.61 -151.77 0.753
2 A' A'   1451 1267 184.1 1.145   3.100 1.197 1.903 2.589   577.87 1646.76 -1068.89 0.351
3 A' A'   795 974 -179.5 0.816   1.286 1.244 0.041 1.033   80.47 158.17 -77.70 0.509
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.