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Compare vibrational frequencies for two calculations for NH2COOH (Carbamic acid)


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

scale factors=0.8985, 0.943 0.126 0.107 -0.380 -0.108 1.293
  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'   3673 3593 79.8 1.022   1.066 1.107 -0.041 0.963   136.42 83.54 1.633
2 A' A'   3592 3533 58.6 1.017   1.108 1.065 0.044 1.041   89.58 88.19 1.016
3 A' A'   3472 3462 10.0 1.003   1.046 1.045 0.001 1.001   74.00 80.64 0.918
4 A' A'   1813 1787 25.8 1.014   8.088 8.168 -0.080 0.990   689.22 468.27 1.472
5 A' A'   1606 1560 46.3 1.030   1.300 1.322 -0.021 0.984   165.83 147.98 1.121
6 A' A'   1426 1391 35.2 1.025   2.870 2.744 1.046   189.15 133.74 1.414
7 A' A'   1228 1187 41.1 1.035   1.586 1.480 1.072   228.06 211.00 1.081
8 A' A'   1072 1040 32.1 1.031   1.659 1.735 -0.076 0.956   46.16 32.52 1.419
9 A' A'   958 917 41.2 1.045   4.246 4.625 0.918   20.08 43.42 0.462
10 A' A'   580 550 29.4 1.053   4.432 4.540 0.976   49.97 36.87 1.355
11 A' A'   479 463 15.9 1.034   2.737 2.718 0.019 1.007   6.49 6.59 0.985
12 A" A"   788 727 61.0 1.084   9.705 8.412 1.154   86.34 34.76 2.484
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.