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

Compare vibrational frequencies for two calculations for N3- (azide 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   1410 1356 53.7 1.040   14.003 14.003 0.000 1.000   0.00 0.00 0.00  
2 Σu Σu   2062 5585 -3523.0 0.369   14.003 14.003 0.000 1.000   1589.83 0.00 1589.83  
3 Πu Πu   701 574 126.8 1.221   14.003 14.003 0.000 1.000   38.59 8.71 29.87 4.428
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.