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Compare vibrational frequencies for two calculations for HOBr+ (Hypobromous acid cation)


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

scale factors=0.8985, 0.943 -0.105 8.485
  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'   3477 3209 268.2 1.084   1.069 1.069 -0.001 0.999   495.10 815.72 0.607
2 A' A'   1201 1126 74.8 1.066   1.073 1.178 0.911   123.92 254.32 0.487
3 A' A'   765 949 -184.3 0.806   15.198 6.713 2.264   36.99 1.24 29.899
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.