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

Compare vibrational frequencies for two calculations for C5H5NO (2(3H)-Pyridinone)

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   3052 3074 -21.5 0.993   1.100 1.099 0.001 1.001   15.92 9.70 6.22 1.642
2 A A   3027 3050 -23.2 0.992   1.089 1.089 0.001 1.001   9.01 2.70 6.31 3.340
3 A A   2993 3000 -7.2 0.998   1.092 1.090 0.001 1.001   38.73 30.82 7.91 1.257
4 A A   2931 2992 -61.2 0.980   1.093 1.093 0.000 1.000   4.27 1.22 3.05 3.499
5 A A   2876 2890 -13.9 0.995   1.070 1.069 0.001 1.001   4.91 0.67 4.24 7.277
6 A A   1818 1697 121.4 1.072   12.544 11.927 0.617 1.052   400.82 169.75 231.07 2.361
7 A A   1703 1612 90.6 1.056   6.227 5.575 0.652 1.117   96.71 22.96 73.75 4.212
8 A A   1627 1534 92.2 1.060   8.958 9.130 -0.172 0.981   185.01 52.28 132.74 3.539
9 A A   1417 1407 10.0 1.007   1.128 1.092 0.036 1.033   5.39 18.36 -12.97 0.294
10 A A   1406 1371 34.8 1.025   1.592 1.643 -0.050 0.969   64.30 26.33 37.96 2.442
11 A A   1381 1349 31.9 1.024   1.407 1.398 0.009 1.006   10.26 8.84 1.41 1.160
12 A A   1336 1277 58.2 1.046   1.736 1.837 -0.101 0.945   4.09 7.85 -3.75 0.522
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.