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Compare vibrational frequencies for two calculations for CH3COCH2 (Acetonyl radical)


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

scale factors=0.8985, 0.943 -10.140 0.190 0.682 0.198 0.185 -0.182
  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'   3100 3175 -75.3 0.976   1.121 1.121 -0.001 0.999   5.32 2.57 2.071
2 A' A'   3001 3065 -63.9 0.979   1.053 1.104 -0.051 0.954   7.20 4.64 1.551
3 A' A'   2979 3054 -74.5 0.976   1.102 1.051 0.051 1.048   11.09 0.70 15.819
4 A' A'   2883 2935 -51.6 0.982   1.039 1.037 0.002 1.002   11.26 0.26 43.349
5 A' A'   1462 1985 -522.6 0.737   1.855 11.995 0.155   35.82 775.10 0.046
6 A' A'   1457 1442 15.9 1.011   1.058 1.054 0.004 1.004   8.17 11.95 0.684
7 A' A'   1402 1417 -15.3 0.989   1.415 1.226 1.155   15.61 31.04 0.503
8 A' A'   1383 1360 23.3 1.017   2.053 1.370 1.498   2.69 47.00 0.057
9 A' A'   1217 1222 -5.3 0.996   2.881 2.683 1.074   55.22 102.87 0.537
10 A' A'   1033 1039 -5.8 0.994   1.787 1.602 1.115   1.95 7.03 0.277
11 A' A'   907 866 41.2 1.048   1.607 1.593 0.014 1.009   12.47 14.48 0.861
12 A' A'   796 783 12.3 1.016   3.258 3.440 0.947   0.11 1.00 0.108
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.