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

Compare vibrational frequencies for two calculations for N(CH3)2CONH2 (Urea, N,N-dimethyl-)

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   3541 3501 40.7 1.012   1.101 1.099 0.003 1.003   38.91 27.59 11.31 1.410
2 A A   3440 3389 50.7 1.015   1.049 1.048 0.001 1.001   37.74 27.78 9.96 1.359
3 A A   3029 3070 -40.9 0.987   1.097 1.101 -0.003 0.997   4.50 2.06 2.44 2.186
4 A A   2977 3030 -52.7 0.983   1.099 1.104 -0.005 0.995   29.26 20.70 8.56 1.414
5 A A   2932 3000 -67.8 0.977   1.097 1.097 -0.000 1.000   44.71 22.03 22.68 2.029
6 A A   2924 2996 -71.1 0.976   1.106 1.097 0.009 1.008   56.21 31.74 24.47 1.771
7 A A   2880 2914 -34.0 0.988   1.042 1.043 -0.001 0.999   37.52 47.87 -10.35 0.784
8 A A   2871 2909 -38.1 0.987   1.045 1.043 0.003 1.003   78.65 39.13 39.53 2.010
9 A A   1751 1714 36.7 1.021   6.837 6.868 -0.031 0.996   520.67 313.09 207.57 1.663
10 A A   1625 1585 40.6 1.026   1.231 1.214 0.018 1.015   168.26 149.46 18.80 1.126
11 A A   1506 1492 13.8 1.009   1.200 1.139 0.061 1.054   84.64 38.08 46.55 2.222
12 A A   1493 1473 20.2 1.014   1.054 1.049 0.004 1.004   2.13 23.66 -21.54 0.090
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.