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

Compare vibrational frequencies for two calculations for C4H9N (Cyclobutylamine)

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'   3339 3295 43.7 1.013   1.051 1.050 0.001 1.001   0.62 0.52 0.10 1.202
2 A' A'   2966 3033 -67.5 0.978   1.107 1.107 -0.000 1.000   79.27 29.85 49.41 2.655
3 A' A'   2936 2999 -63.0 0.979   1.109 1.109 -0.000 1.000   26.03 25.36 0.67 1.027
4 A' A'   2917 2963 -46.5 0.984   1.064 1.063 0.002 1.002   43.82 32.39 11.43 1.353
5 A' A'   2899 2943 -43.5 0.985   1.062 1.060 0.002 1.002   43.97 13.21 30.76 3.328
6 A' A'   2840 2871 -31.4 0.989   1.086 1.086 -0.000 1.000   100.61 83.85 16.76 1.200
7 A' A'   1647 1617 29.4 1.018   1.097 1.091 0.005 1.005   31.22 25.99 5.23 1.201
8 A' A'   1490 1477 13.2 1.009   1.147 1.141 0.006 1.005   2.83 4.06 -1.23 0.697
9 A' A'   1459 1451 7.3 1.005   1.092 1.086 0.007 1.006   1.63 2.65 -1.02 0.616
10 A' A'   1377 1351 25.7 1.019   1.477 1.494 -0.017 0.989   30.27 21.80 8.47 1.388
11 A' A'   1295 1257 38.3 1.031   1.558 1.626 -0.068 0.958   1.52 6.43 -4.91 0.237
12 A' A'   1220 1204 16.3 1.014   1.282 1.298 -0.016 0.988   2.98 1.09 1.89 2.732
13 A' A'   1146 1131 15.6 1.014   2.256 2.227 0.029 1.013   15.29 8.36 6.93 1.829
14 A' A'   1051 1063 -11.4 0.989   2.271 2.190 0.081 1.037   8.72 8.81 -0.08 0.991
15 A' A'   929 948 -18.6 0.980   2.315 2.154 0.161 1.075   15.27 14.03 1.24 1.088
16 A' A'   876 880 -3.9 0.996   1.669 1.841 -0.172 0.906   112.04 43.27 68.77 2.589
17 A' A'   863 861 1.8 1.002   2.078 2.047 0.031 1.015   11.62 44.94 -33.32 0.259
18 A' A'   799 815 -15.7 0.981   1.852 1.661 0.191 1.115   24.12 43.41 -19.28 0.556
19 A' A'   658 648 10.0 1.015   1.508 1.597 -0.089 0.944   0.83 1.40 -0.56 0.597
20 A' A'   389 394 -4.7 0.988   2.289 2.242 0.047 1.021   5.17 4.90 0.28 1.057
21 A' A'   149 194 -45.8 0.764   1.989 2.055 -0.066 0.968   1.57 2.10 -0.53 0.746
22 A" A"   3413 3391 22.3 1.007   1.094 1.092 0.001 1.001   0.14 0.19 -0.05 0.719
23 A" A"   2941 3001 -60.6 0.980   1.109 1.109 -0.001 0.999   18.06 10.51 7.55 1.719
24 A" A"   2896 2939 -43.3 0.985   1.060 1.058 0.002 1.002   86.56 54.33 32.23 1.593
25 A" A"   1456 1444 12.4 1.009   1.104 1.096 0.008 1.008   0.38 1.57 -1.19 0.244
26 A" A"   1337 1310 27.5 1.021   1.716 1.733 -0.017 0.990   1.41 0.06 1.34 22.775
27 A" A"   1267 1240 27.1 1.022   1.357 1.273 0.084 1.066   0.27 1.00 -0.73 0.273
28 A" A"   1256 1220 35.9 1.029   1.331 1.357 -0.026 0.981   0.42 0.12 0.30 3.553
29 A" A"   1205 1187 18.2 1.015   1.262 1.303 -0.042 0.968   0.23 0.59 -0.36 0.395
30 A" A"   1155 1127 27.6 1.024   1.109 1.139 -0.030 0.974   0.51 0.82 -0.32 0.616
31 A" A"   1013 1001 11.5 1.012   1.078 1.076 0.002 1.002   0.29 0.16 0.13 1.800
32 A" A"   910 922 -11.5 0.987   2.355 2.305 0.050 1.022   0.36 0.58 -0.22 0.618
33 A" A"   895 901 -5.9 0.993   1.815 1.807 0.009 1.005   2.77 2.25 0.53 1.235
34 A" A"   750 757 -7.5 0.990   1.333 1.334 -0.001 0.999   0.48 1.00 -0.52 0.482
35 A" A"   378 375 3.6 1.010   2.024 1.977 0.047 1.024   12.08 12.77 -0.69 0.946
36 A" A"   282 283 -0.1 1.000   1.108 1.125 -0.017 0.985   37.70 34.95 2.75 1.079
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.