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Compare vibrational frequencies for two calculations for CH2F (fluoromethyl radical)


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

scale factors=0.8985, 0.943 0.247 5.059 -4.868 -0.144
  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'   775 3036 -2261.5 0.255   1.288 1.041 1.237   14.37 13.50 1.065
2 A' A'   1141 1457 -315.8 0.783   6.208 1.149 5.405   132.03 9.87 13.383
3 A" A'   1151 1137 13.8 1.012   1.218 6.086 0.200   12.33 102.51 0.120
4 A' A'   1452 727 725.6 1.998   1.146 1.289 0.889   15.33 25.77 0.595
5 A' A"   2981 3181 -200.4 0.937   1.042 1.129 -0.087 0.923   17.15 19.81 0.866
6 A" A"   3107 1144 1963.5 2.717   1.127 1.219 -0.091 0.925   32.40 7.23 4.482
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.