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Compare vibrational frequencies for two calculations for NNH (Dinitrogen monohydride)


A = HF/6-31G*
B = MP2/6-31G*

scale factors=0.8985, 0.943 -1.257 10.234
  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'   3081 2806 275.6 1.098   1.069 2.326 0.460   0.12 107.98 0.001
2 A' A'   1844 2666 -821.7 0.692   11.949 1.715 6.967   23.93 69.54 0.344
3 A' A'   1135 1005 129.9 1.129   1.204 1.220 -0.016 0.987   128.50 164.83 0.780
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.