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III.G.7. (XIII.B.3.) (XIII.D.5.)

Compare vibrational frequencies for two calculations for C6H8 (3-Methylenecyclopentene)

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   3056 3109 -52.6 0.983   1.116 1.117 -0.002 0.998   34.78 10.64 24.13 3.268
2 A A   3054 3075 -21.2 0.993   1.107 1.104 0.003 1.002   10.73 15.51 -4.78 0.692
3 A A   3031 3054 -23.4 0.992   1.087 1.087 0.001 1.001   6.36 1.75 4.61 3.629
4 A A   2989 3024 -35.2 0.988   1.062 1.060 0.002 1.002   11.48 4.15 7.33 2.769
5 A A   2936 2991 -55.3 0.982   1.106 1.104 0.002 1.002   42.98 19.64 23.34 2.189
6 A A   2904 2963 -58.4 0.980   1.062 1.101 -0.039 0.965   37.34 17.17 20.17 2.175
7 A A   2898 2935 -37.5 0.987   1.106 1.064 0.042 1.039   20.67 13.56 7.11 1.524
8 A A   2878 2917 -39.7 0.986   1.061 1.063 -0.002 0.998   55.11 30.05 25.06 1.834
9 A A   1695 1635 59.6 1.036   5.836 5.841 -0.005 0.999   36.73 7.40 29.33 4.964
10 A A   1633 1563 69.5 1.044   5.601 5.352 0.249 1.047   0.62 0.09 0.54 7.313
11 A A   1484 1470 13.7 1.009   1.104 1.104 0.000 1.000   0.81 2.29 -1.48 0.353
12 A A   1457 1446 10.4 1.007   1.088 1.087 0.001 1.001   0.52 1.60 -1.08 0.327
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.