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

Compare vibrational frequencies for two calculations for C5H5NO (3-Pyridinol)

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'   3693 3533 160.1 1.045   1.067 1.066 0.001 1.001   89.26 64.26 25.00 1.389
2 A' A'   3057 3072 -15.5 0.995   1.099 1.098 0.000 1.000   10.95 3.99 6.96 2.743
3 A' A'   3044 3060 -16.0 0.995   1.094 1.093 0.001 1.001   24.17 12.06 12.12 2.005
4 A' A'   3029 3044 -15.0 0.995   1.089 1.089 -0.000 1.000   7.32 7.06 0.26 1.037
5 A' A'   2998 3002 -4.0 0.999   1.091 1.091 0.000 1.000   39.58 25.55 14.03 1.549
6 A' A'   1626 1576 50.2 1.032   6.150 5.758 0.392 1.068   18.68 18.38 0.30 1.016
7 A' A'   1618 1562 55.3 1.035   5.410 5.753 -0.343 0.940   19.01 24.64 -5.63 0.771
8 A' A'   1502 1457 45.0 1.031   2.380 2.325 0.055 1.024   26.84 24.52 2.33 1.095
9 A' A'   1449 1412 36.3 1.026   2.516 2.417 0.100 1.041   145.11 109.91 35.20 1.320
10 A' A'   1348 1355 -6.9 0.995   1.221 9.033 -7.811 0.135   23.87 1.68 22.18 14.182
11 A' A'   1276 1318 -42.7 0.968   2.890 1.225 1.665 2.359   83.68 26.64 57.04 3.141
12 A' A'   1215 1255 -39.7 0.968   1.436 2.462 -1.026 0.583   148.71 59.66 89.05 2.493
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.