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Compare vibrational frequencies for two calculations for HCS (Thioformyl radical)


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

scale factors=0.8985, 0.943 -1.621
  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'   3033 3009 23.9 1.008   1.089 1.108 -0.019 0.983   7.97 47.46 0.168
2 A' A'   928 1517 -589.2 0.612   7.070 8.691 0.813   0.90 296.82 0.003
3 A' A'   887 845 41.4 1.049   1.234 1.183 0.051 1.043   26.42 148.58 0.178
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.