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Compare vibrational frequencies for two calculations for FHF- (FHF-)


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   602 589 13.6 1.023   18.998 18.998 0.000 1.000   0.00 0.00  
2 Σu Σu   1225 1515 -290.1 0.808   1.033 1.033 0.000 1.000   3073.70 2681.59 1.146
3 Πu Πu   1230 1168 61.3 1.052   1.033 1.033 0.000 1.000   160.17 130.01 1.232
4 Πu Πu   1230 1168 61.3 1.052   1.033 1.033 0.000 1.000   160.17 130.01 1.232
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.