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Compare vibrational frequencies for two calculations for C4H6OS (4,5-dihydrothiophene-3-ol)


A = HF/6-31G*
B = MP2/6-31G*

scale factors=0.8985, 0.943 0.740 -0.166
  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   3694 3549 144.8 1.041   1.067 1.066 0.001 1.001   87.11 59.96 1.453
2 A A   3084 3110 -26.2 0.992   1.096 1.095 0.001 1.001   7.69 5.29 1.453
3 A A   2982 3027 -44.7 0.985   1.107 1.107 -0.001 1.000   15.60 6.91 2.257
4 A A   2928 2960 -31.4 0.989   1.064 1.073 -0.010 0.991   44.03 28.57 1.541
5 A A   2895 2948 -52.3 0.982   1.104 1.091 0.013 1.012   20.02 5.34 3.750
6 A A   2868 2901 -32.6 0.989   1.060 1.060 -0.000 1.000   50.10 29.02 1.726
7 A A   1708 1635 72.6 1.044   6.947 6.207 1.119   57.46 24.11 2.383
8 A A   1478 1457 20.3 1.014   1.114 1.113 0.001 1.001   3.16 2.06 1.532
9 A A   1458 1442 16.1 1.011   1.092 1.091 0.001 1.001   0.92 3.25 0.283
10 A A   1368 1328 40.4 1.030   2.391 2.557 0.935   119.86 106.90 1.121
11 A A   1304 1285 18.6 1.014   1.342 1.264 0.078 1.062   33.54 13.06 2.569
12 A A   1286 1251 34.8 1.028   1.351 1.406 -0.055 0.961   68.89 64.28 1.072
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.