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

Compare vibrational frequencies for two calculations for PO2- (Phosphorus dioxide 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 Σg Σg   1128 1002 125.9 1.126   15.995 15.995 0.000 1.000   0.00 0.00 0.00  
2 Σu Σu   1585 1538 46.8 1.030   21.205 21.205 0.000 1.000   83.19 7.55 75.63 11.016
3 Πu Πu   299 236 62.8 1.266   21.205 21.205 0.000 1.000   96.95 35.28 61.68 2.748
4 Πu Πu   299 236 62.8 1.266   21.205 21.205 0.000 1.000   96.95 35.28 61.68 2.748
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.