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

Compare vibrational frequencies for two calculations for CS2+ (Carbon disulfide cation)

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 Σg Σg   595 677 -81.8 0.879   31.972 31.972 0.000 1.000   0.00 0.00 0.00  
2 Σu Σu   1035 1014 21.2 1.021   13.314 13.314 0.000 1.000   381.93 11.40 370.53 33.494
3 Πu Πu   357 369 -11.7 0.968   13.314 13.314 0.000 1.000   0.82 5.49 -4.67 0.150
4 Πu Πu   279 342 -62.7 0.816   13.314 13.314 0.000 1.000   0.66 2.07 -1.41 0.317
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.