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Compare vibrational frequencies for two calculations for CH2C(CH3)OCH3 (1-Propene, 2-methoxy-)


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)
mode number A B   A B diff. ratio   A B diff. ratio   A B diff. ratio
1 A A   3089 3147 -58.4 0.981   1.119 1.119 -0.000 1.000   13.57 5.37 2.528
2 A A   3013 3053 -39.7 0.987   1.063 1.060 0.003 1.002   2.64 0.48 5.512
3 A A   2982 3041 -59.2 0.981   1.102 1.103 -0.001 0.999   40.39 19.66 2.054
4 A A   2967 3030 -62.6 0.979   1.101 1.102 -0.001 0.999   27.70 13.95 1.986
5 A A   2933 3001 -67.8 0.977   1.105 1.102 0.003 1.003   49.39 10.76 4.590
6 A A   2926 2987 -60.9 0.980   1.102 1.107 -0.005 0.995   49.04 42.88 1.144
7 A A   2883 2928 -45.7 0.984   1.039 1.037 0.002 1.002   51.01 14.61 3.491
8 A A   2876 2910 -33.6 0.988   1.036 1.033 0.003 1.003   24.94 42.45 0.588
9 A A   1702 1651 50.6 1.031   5.323 5.374 -0.052 0.990   117.07 68.10 1.719
10 A A   1493 1483 9.4 1.006   1.049 1.051 -0.002 0.998   5.90 4.72 1.248
11 A A   1486 1476 10.6 1.007   1.069 1.060 0.009 1.008   7.05 10.60 0.665
12 A A   1474 1465 9.7 1.007   1.089 1.059 0.029 1.028   5.79 10.25 0.565
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.