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Compare vibrational frequencies for two calculations for C5H8O (Cyclopentanone)


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

scale factors=0.8985, 0.943 11.212 0.348 -11.082 0.357 0.300 0.715
  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   2952 3004 -52.5 0.983   1.096 1.104 -0.008 0.993   6.28 25.97 0.242
2 A A   2938 3001 -62.7 0.979   1.094 1.100 -0.006 0.994   34.44 6.28 5.484
3 A A   2885 2996 -111.4 0.963   1.067 1.100 -0.033 0.970   29.92 15.94 1.877
4 A A   2884 2992 -107.8 0.964   1.078 1.100 -0.022 0.980   1.28 11.48 0.112
5 A A   1834 2937 -1102.9 0.625   12.273 1.061 11.567   301.60 27.33 11.037
6 A A   1491 2934 -1443.7 0.508   1.111 1.066 0.045 1.042   0.46 19.51 0.024
7 A A   1439 2926 -1486.6 0.492   1.090 1.067 0.023 1.021   0.08 4.82 0.016
8 A A   1335 2925 -1590.1 0.456   1.415 1.067 1.326   0.51 5.60 0.091
9 A A   1303 1709 -405.7 0.763   1.385 12.468 0.111   0.00 138.09 0.000
10 A A   1205 1481 -275.8 0.814   1.464 1.108 1.322   0.33 1.25 0.265
11 A A   1166 1468 -301.9 0.794   1.387 1.087 1.276   1.77 5.68 0.312
12 A A   996 1429 -433.7 0.697   1.804 1.089 1.657   0.36 19.10 0.019
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.