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

Compare vibrational frequencies for two calculations for CH3COCH3 (Acetone)

A = HF/6-31G*

B = MP2FC/6-31G*

  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 A1 A1   2987 3051 -64.6 0.979   1.103 1.104 -0.001 0.999   14.02 5.02 8.99 2.789
2 A1 A1   2885 2932 -46.6 0.984   1.039 1.037 0.003 1.003   12.05 4.65 7.40 2.590
3 A1 A1   1816 1690 126.8 1.075   10.562 8.724 1.839 1.211   229.43 89.55 139.88 2.562
4 A1 A1   1450 1447 3.4 1.002   1.055 1.072 -0.017 0.984   20.96 25.03 -4.07 0.837
5 A1 A1   1389 1361 28.4 1.021   1.241 1.239 0.002 1.002   8.05 14.01 -5.96 0.574
6 A1 A1   1070 1051 18.4 1.017   1.530 1.552 -0.022 0.986   0.59 0.12 0.48 5.112
7 A1 A1   760 768 -8.1 0.989   3.567 3.625 -0.058 0.984   0.04 0.79 -0.75 0.048
8 A1 A1   360 363 -2.7 0.993   2.224 2.194 0.030 1.014   1.31 1.00 0.31 1.306
9 A2 A2   2927 3003 -75.4 0.975   1.100 1.101 -0.000 1.000   0.00 0.00 0.00  
10 A2 A2   1447 1441 5.7 1.004   1.052 1.055 -0.003 0.997   0.00 0.00 0.00  
11 A2 A2   881 870 11.1 1.013   1.206 1.203 0.004 1.003   0.00 0.00 0.00  
12 A2 A2   48 57 -8.9 0.844   1.018 1.019 -0.001 0.999   0.00 0.00 0.00  
13 B1 B1   2935 3008 -73.1 0.976   1.101 1.101 0.000 1.000   38.72 14.56 24.16 2.659
14 B1 B1   1467 1461 6.0 1.004   1.045 1.046 -0.001 0.999   18.40 22.25 -3.85 0.827
15 B1 B1   1114 1090 23.8 1.022   1.936 1.891 0.046 1.024   3.03 2.98 0.05 1.017
16 B1 B1   477 463 14.1 1.030   2.030 2.052 -0.022 0.989   2.75 0.33 2.42 8.280
17 B1 B1   130 133 -3.5 0.974   1.126 1.131 -0.005 0.995   0.08 0.03 0.05 2.974
18 B2 B2   2986 3051 -65.0 0.979   1.102 1.104 -0.002 0.998   15.24 6.94 8.30 2.196
19 B2 B2   2878 2927 -49.1 0.983   1.040 1.037 0.003 1.003   3.55 1.12 2.43 3.161
20 B2 B2   1444 1441 3.3 1.002   1.046 1.044 0.002 1.002   0.00 0.59 -0.59 0.004
21 B2 B2   1397 1366 31.1 1.023   1.469 1.494 -0.025 0.983   49.36 67.54 -18.19 0.731
22 B2 B2   1215 1213 1.8 1.001   2.608 2.636 -0.028 0.989   76.35 60.98 15.37 1.252
23 B2 B2   884 875 8.6 1.010   1.547 1.517 0.030 1.020   3.61 3.60 0.01 1.003
24 B2 B2   517 507 9.6 1.019   3.605 3.585 0.019 1.005   23.11 15.23 7.88 1.517
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.