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

Compare vibrational frequencies for two calculations for N2O- (Nitrous oxide 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   2366 3102 -736.2 0.763   14.032 14.009 0.023 1.002   490.12 56.86 433.27 8.620
2 Σ Σ   1252 1215 36.9 1.030   15.175 14.889 0.286 1.019   164.89 7.90 156.99 20.869
3 Π Π   619 607 12.4 1.020   14.247 14.234 0.013 1.001   19.62 1.73 17.89 11.362
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.