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Compare vibrational frequencies for two calculations for N2O- (Nitrous oxide anion)


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 A' A'   1288 2859 -1571.1 0.451   14.025 14.006 0.019 1.001   69.14 1231.17 0.056
2 A' A'   1027 1082 -55.0 0.949   14.925 15.001 -0.076 0.995   267.62 227.79 1.175
3 A' A'   499 677 -178.0 0.737   14.533 14.443 0.090 1.006   6.97 26.03 0.268
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.