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Compare vibrational frequencies for two calculations for C4H6OS (2,3-dihydrothiophene-2-ol)


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

scale factors=0.8985, 0.943 0.242
  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   3691 3537 153.9 1.044   1.067 1.066 0.001 1.001   69.55 38.49 1.807
2 A A   3073 3100 -26.9 0.991   1.102 1.101 0.001 1.000   12.59 5.82 2.164
3 A A   3040 3072 -32.4 0.989   1.089 1.088 0.001 1.001   4.68 0.79 5.907
4 A A   2931 2990 -58.3 0.981   1.101 1.099 0.002 1.002   54.18 5.39 10.046
5 A A   2906 2937 -31.5 0.989   1.089 1.086 0.003 1.003   23.32 39.87 0.585
6 A A   2887 2914 -26.8 0.991   1.064 1.066 -0.003 0.997   26.90 9.03 2.978
7 A A   1641 1559 81.6 1.052   6.456 6.214 1.039   7.80 5.64 1.381
8 A A   1468 1435 32.7 1.023   1.112 1.108 0.005 1.004   1.71 4.11 0.417
9 A A   1415 1347 68.2 1.051   1.430 1.456 -0.026 0.982   6.00 8.80 0.682
10 A A   1338 1308 30.0 1.023   1.676 1.645 0.031 1.019   13.90 6.35 2.189
11 A A   1304 1281 23.0 1.018   1.300 1.328 -0.028 0.979   21.18 25.51 0.830
12 A A   1276 1248 28.4 1.023   1.232 1.283 -0.051 0.960   20.92 59.59 0.351
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.