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

Compare vibrational frequencies for two calculations for C6H4 (Benzyne)

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   3063 3071 -7.7 0.997   1.096 1.097 -0.001 0.999   5.90 4.86 1.04 1.215
2 A1 A1   3029 3049 -19.9 0.993   1.093 1.092 0.000 1.000   15.80 3.21 12.60 4.931
3 A1 A1   1987 1845 142.6 1.077   11.229 11.250 -0.021 0.998   0.04 3.27 -3.22 0.013
4 A1 A1   1447 1436 11.6 1.008   2.215 3.337 -1.121 0.664   0.15 0.19 -0.05 0.761
5 A1 A1   1260 1324 -63.4 0.952   1.822 2.503 -0.680 0.728   0.42 1.24 -0.82 0.336
6 A1 A1   1118 1133 -14.9 0.987   1.474 1.089 0.385 1.353   0.64 0.78 -0.14 0.820
7 A1 A1   978 1022 -43.7 0.957   4.912 3.272 1.640 1.501   30.13 20.33 9.80 1.482
8 A1 A1   967 963 4.0 1.004   2.491 2.776 -0.285 0.897   4.77 2.31 2.46 2.062
9 A1 A1   603 580 22.9 1.039   7.287 7.251 0.036 1.005   0.77 0.09 0.68 8.549
10 A2 A2   988 838 150.6 1.180   1.336 1.092 0.244 1.223   0.00 0.00 0.00  
11 A2 A2   872 802 70.5 1.088   1.259 1.269 -0.010 0.992   0.00 0.00 0.00  
12 A2 A2   569 520 48.8 1.094   2.889 9.539 -6.650 0.303   0.00 0.00 0.00  
13 A2 A2   399 442 -43.1 0.903   10.270 5.623 4.647 1.826   0.00 0.00 0.00  
14 B1 B1   944 824 119.4 1.145   1.362 1.298 0.064 1.049   0.04 0.83 -0.80 0.044
15 B1 B1   754 702 51.8 1.074   1.229 1.248 -0.019 0.985   76.28 74.27 2.00 1.027
16 B1 B1   388 364 23.5 1.064   2.750 2.937 -0.187 0.936   6.04 4.59 1.44 1.314
17 B2 B2   3060 3068 -8.3 0.997   1.094 1.095 -0.001 0.999   43.34 19.66 23.68 2.205
18 B2 B2   3013 3036 -22.8 0.992   1.088 1.086 0.001 1.001   5.01 0.40 4.62 12.595
19 B2 B2   1482 1436 45.5 1.032   3.401 4.091 -0.690 0.831   24.85 0.96 23.89 25.987
20 B2 B2   1388 1361 27.1 1.020   2.209 2.474 -0.266 0.893   3.26 13.61 -10.34 0.240
21 B2 B2   1233 1219 13.8 1.011   1.654 1.421 0.233 1.164   0.08 0.09 -0.01 0.849
22 B2 B2   1088 1076 11.6 1.011   1.477 1.484 -0.007 0.995   0.83 0.62 0.21 1.334
23 B2 B2   810 831 -20.4 0.975   6.272 6.662 -0.390 0.942   33.47 9.94 23.53 3.367
24 B2 B2   284 557 -273.6 0.509   10.751 9.540 1.210 1.127   189.90 10.12 179.78 18.774
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.