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

Compare vibrational frequencies for two calculations for C4H6OS (4,5-dihydrothiophene-3-ol)

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   3694 3549 144.8 1.041   1.067 1.066 0.001 1.001   87.11 59.98 27.13 1.452
2 A A   3084 3110 -26.2 0.992   1.096 1.095 0.001 1.001   7.69 5.29 2.40 1.454
3 A A   2982 3027 -44.6 0.985   1.107 1.107 -0.001 1.000   15.60 6.92 8.68 2.254
4 A A   2928 2960 -31.4 0.989   1.064 1.073 -0.010 0.991   44.03 28.54 15.49 1.543
5 A A   2895 2948 -52.3 0.982   1.104 1.091 0.013 1.012   20.02 5.35 14.67 3.740
6 A A   2868 2901 -32.6 0.989   1.060 1.060 -0.000 1.000   50.10 29.03 21.06 1.725
7 A A   1708 1635 72.8 1.045   6.947 6.204 0.743 1.120   57.46 24.09 33.37 2.385
8 A A   1478 1457 20.3 1.014   1.114 1.113 0.001 1.001   3.16 2.06 1.10 1.532
9 A A   1458 1442 16.1 1.011   1.092 1.091 0.001 1.001   0.92 3.26 -2.34 0.283
10 A A   1368 1328 40.4 1.030   2.391 2.557 -0.166 0.935   119.86 106.93 12.93 1.121
11 A A   1304 1285 18.6 1.015   1.342 1.264 0.078 1.061   33.54 13.04 20.50 2.572
12 A A   1286 1251 34.8 1.028   1.351 1.406 -0.055 0.961   68.89 64.27 4.62 1.072
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.