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Compare vibrational frequencies for two calculations for C5H11 (2-Methylbut-2-yl radical)


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)   Raman Activity (Å4/u)
mode number A B   A B diff. ratio   A B diff. ratio   A B diff. ratio   A B diff. ratio
1 A A   2944 3021 -76.5 0.975   1.101 1.103 -0.002 0.999   50.11 26.24 23.88 1.910          
2 A A   2936 3013 -76.7 0.975   1.103 1.103 -0.000 1.000   74.62 18.99 55.63 3.929          
3 A A   2932 3009 -77.1 0.974   1.103 1.103 0.001 1.001   72.15 37.95 34.20 1.901          
4 A A   2929 3001 -72.4 0.976   1.103 1.103 0.000 1.000   16.82 18.67 -1.85 0.901          
5 A A   2906 2965 -58.6 0.980   1.075 1.080 -0.005 0.995   43.28 20.78 22.50 2.082          
6 A A   2896 2956 -59.5 0.980   1.076 1.082 -0.006 0.995   35.53 23.22 12.30 1.530          
7 A A   2885 2935 -50.1 0.983   1.081 1.090 -0.009 0.992   16.82 20.48 -3.66 0.821          
8 A A   2878 2931 -52.8 0.982   1.043 1.036 0.007 1.007   35.41 20.58 14.83 1.721          
9 A A   2825 2866 -41.7 0.985   1.060 1.052 0.008 1.008   78.01 37.29 40.73 2.092          
10 A A   2819 2863 -43.9 0.985   1.058 1.052 0.006 1.006   28.91 24.02 4.89 1.204          
11 A A   2803 2839 -36.2 0.987   1.073 1.070 0.003 1.003   39.41 32.71 6.70 1.205          
12 A A   1487 1485 2.4 1.002   1.057 1.053 0.004 1.004   0.79 1.55 -0.76 0.509          
13 A A   1480 1477 2.8 1.002   1.051 1.047 0.004 1.004   4.56 6.60 -2.04 0.691          
14 A A   1474 1471 2.8 1.002   1.051 1.061 -0.010 0.990   5.09 3.06 2.04 1.666          
15 A A   1472 1464 7.9 1.005   1.055 1.056 -0.001 0.999   9.72 18.16 -8.44 0.535          
16 A A   1467 1461 6.2 1.004   1.061 1.062 -0.001 0.999   1.29 1.81 -0.52 0.713          
17 A A   1461 1452 8.5 1.006   1.057 1.062 -0.005 0.995   1.12 2.57 -1.44 0.438          
18 A A   1456 1449 7.8 1.005   1.062 1.065 -0.002 0.998   0.53 0.52 0.02 1.032          
19 A A   1411 1391 20.1 1.014   1.230 1.236 -0.006 0.995   2.80 4.62 -1.82 0.606          
20 A A   1406 1385 20.6 1.015   1.277 1.276 0.001 1.001   0.80 2.39 -1.59 0.336          
21 A A   1397 1377 20.1 1.015   1.315 1.376 -0.061 0.956   1.97 5.77 -3.80 0.341          
22 A A   1363 1347 15.8 1.012   1.532 1.734 -0.201 0.884   0.54 0.15 0.39 3.565          
23 A A   1279 1280 -0.9 0.999   1.401 2.293 -0.892 0.611   0.80 1.03 -0.23 0.775          
24 A A   1247 1250 -3.4 0.997   2.051 1.362 0.689 1.506   5.61 4.98 0.64 1.128          
25 A A   1208 1219 -11.4 0.991   2.367 2.153 0.213 1.099   5.35 5.30 0.05 1.009          
26 A A   1093 1095 -2.2 0.998   1.675 1.707 -0.032 0.981   1.83 0.92 0.92 1.997          
27 A A   1033 1047 -13.4 0.987   1.875 2.329 -0.453 0.805   0.66 0.36 0.30 1.815          
28 A A   1012 1020 -8.2 0.992   1.653 1.522 0.131 1.086   2.32 4.66 -2.34 0.497          
29 A A   976 971 4.7 1.005   1.312 1.240 0.072 1.058   0.53 0.95 -0.42 0.556          
30 A A   962 962 0.6 1.001   1.347 1.306 0.041 1.031   1.10 1.59 -0.50 0.689          
31 A A   925 920 4.5 1.005   1.242 1.859 -0.617 0.668   0.13 0.54 -0.41 0.246          
32 A A   902 917 -14.8 0.984   2.049 1.230 0.819 1.666   0.28 0.25 0.03 1.119          
33 A A   751 750 1.0 1.001   1.174 1.171 0.003 1.002   0.79 1.36 -0.58 0.578          
34 A A   700 722 -21.6 0.970   3.030 2.996 0.034 1.011   1.26 1.52 -0.27 0.826          
35 A A   428 439 -11.1 0.975   2.631 2.590 0.041 1.016   0.45 0.75 -0.30 0.594          
36 A A   361 368 -7.4 0.980   2.151 2.090 0.061 1.029   0.12 0.05 0.07 2.549          
37 A A   297 298 -1.0 0.997   1.959 1.803 0.156 1.086   1.43 2.13 -0.70 0.673          
38 A A   263 277 -13.6 0.951   1.609 1.617 -0.007 0.995   0.03 0.00 0.02 7.618          
39 A A   202 209 -6.7 0.968   1.556 1.566 -0.011 0.993   0.60 0.88 -0.28 0.683          
40 A A   130 146 -15.7 0.892   1.055 1.060 -0.005 0.995   0.01 0.01 0.01 2.049          
41 A A   118 134 -16.4 0.878   1.089 1.089 -0.001 0.999   0.05 0.05 0.01 1.124          
42 A A   44 65 -20.9 0.679   1.830 1.892 -0.062 0.967   0.04 0.07 -0.03 0.552          
scaled by     0.8985 0.943
19 08 20 15 07

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.