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

Compare vibrational frequencies for two calculations for C6H5CH3 (toluene)

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 A' A'   3041 3060 -19.3 0.994   1.099 1.099 -0.000 1.000   22.64 14.71 7.92 1.539
2 A' A'   3020 3041 -20.9 0.993   1.092 1.091 0.002 1.001   14.94 3.70 11.24 4.037
3 A' A'   3006 3026 -20.2 0.993   1.087 1.088 -0.001 0.999   9.73 8.18 1.55 1.190
4 A' A'   2925 2997 -72.4 0.976   1.098 1.102 -0.003 0.997   33.16 15.08 18.08 2.199
5 A' A'   2875 2922 -46.7 0.984   1.040 1.036 0.004 1.004   38.19 21.80 16.40 1.752
6 A' A'   1629 1589 40.3 1.025   5.311 5.830 -0.520 0.911   7.59 3.78 3.81 2.007
7 A' A'   1503 1470 32.8 1.022   2.215 2.315 -0.100 0.957   16.48 14.02 2.46 1.175
8 A' A'   1470 1460 9.6 1.007   1.050 1.049 0.001 1.001   4.40 6.38 -1.98 0.690
9 A' A'   1408 1385 23.4 1.017   1.250 1.258 -0.008 0.994   0.51 0.47 0.04 1.084
10 A' A'   1191 1193 -2.0 0.998   2.671 2.764 -0.093 0.966   0.46 0.14 0.32 3.275
11 A' A'   1170 1165 5.3 1.005   1.200 1.137 0.063 1.056   0.32 0.09 0.22 3.372
12 A' A'   1054 1021 33.0 1.032   1.538 1.424 0.115 1.081   6.63 7.29 -0.66 0.909
13 A' A'   1017 1010 7.3 1.007   2.289 2.255 0.034 1.015   1.57 2.09 -0.53 0.749
14 A' A'   1008 966 41.6 1.043   1.310 6.152 -4.842 0.213   0.06 0.13 -0.07 0.470
15 A' A'   979 837 142.1 1.170   6.222 1.072 5.150 5.805   0.04 0.01 0.03 5.971
16 A' A'   914 811 103.3 1.127   1.297 1.234 0.063 1.051   0.74 0.14 0.59 5.120
17 A' A'   766 764 1.7 1.002   4.372 4.538 -0.166 0.963   1.43 0.29 1.14 4.994
18 A' A'   740 682 58.0 1.085   1.290 1.144 0.146 1.128   60.46 68.74 -8.29 0.879
19 A' A'   695 499 195.9 1.393   2.475 5.126 -2.651 0.483   11.29 0.66 10.63 17.078
20 A' A'   506 474 32.0 1.068   4.980 8.027 -3.047 0.620   0.89 0.22 0.67 4.054
21 A' A'   467 426 41.3 1.097   2.783 3.420 -0.638 0.814   7.03 5.34 1.69 1.316
22 A' A'   206 195 11.1 1.057   3.013 3.036 -0.023 0.992   2.09 2.02 0.07 1.034
23 A" A"   3029 3049 -19.9 0.993   1.096 1.095 0.001 1.001   60.30 30.56 29.74 1.973
24 A" A"   3009 3028 -19.0 0.994   1.090 1.089 0.000 1.000   5.59 7.75 -2.16 0.721
25 A" A"   2945 3013 -68.2 0.977   1.104 1.103 0.001 1.001   25.45 10.75 14.70 2.367
26 A" A"   1605 1568 37.0 1.024   5.085 5.343 -0.258 0.952   1.13 0.07 1.06 15.279
27 A" A"   1478 1471 7.3 1.005   1.209 1.105 0.104 1.094   12.32 11.20 1.13 1.101
28 A" A"   1445 1420 25.4 1.018   1.692 2.173 -0.481 0.779   1.36 3.00 -1.65 0.452
29 A" A"   1330 1380 -49.9 0.964   1.314 7.014 -5.699 0.187   0.08 0.14 -0.06 0.583
30 A" A"   1206 1291 -85.4 0.934   1.617 1.304 0.313 1.240   0.00 0.12 -0.12 0.037
31 A" A"   1109 1146 -37.0 0.968   1.649 1.065 0.584 1.548   0.07 0.03 0.04 2.120
32 A" A"   1064 1074 -9.9 0.991   1.829 1.444 0.385 1.267   3.37 4.67 -1.29 0.723
33 A" A"   986 970 15.6 1.016   1.362 1.429 -0.066 0.954   0.00 0.00 -0.00 0.200
34 A" A"   975 833 141.4 1.170   1.536 1.285 0.251 1.196   0.00 0.00 -0.00 0.167
35 A" A"   859 788 71.8 1.091   1.249 1.250 -0.000 1.000   0.01 0.03 -0.02 0.467
36 A" A"   613 600 13.1 1.022   6.365 6.339 0.025 1.004   0.06 0.07 -0.01 0.860
37 A" A"   410 376 33.8 1.090   2.929 3.358 -0.429 0.872   0.00 0.00 -0.00 0.875
38 A" A"   330 325 4.8 1.015   2.530 2.516 0.014 1.005   0.28 0.25 0.04 1.147
39 A" A"   29 56 -26.2 0.529   1.036 1.036 0.000 1.000   0.17 0.20 -0.04 0.814
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.