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III.G.7. (XIII.B.3.) (XIII.D.5.)

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 -58.5 0.981   1.119 1.119 -0.000 1.000   13.57 5.37 8.20 2.528
2 A A   3013 3053 -39.7 0.987   1.063 1.060 0.003 1.002   2.64 0.48 2.15 5.466
3 A A   2982 3041 -59.2 0.981   1.102 1.103 -0.001 0.999   40.39 19.67 20.72 2.053
4 A A   2967 3030 -62.7 0.979   1.101 1.102 -0.001 0.999   27.70 13.95 13.75 1.985
5 A A   2933 3001 -68.0 0.977   1.105 1.102 0.003 1.003   49.39 10.81 38.58 4.570
6 A A   2926 2987 -60.8 0.980   1.102 1.107 -0.005 0.995   49.04 42.85 6.19 1.144
7 A A   2883 2928 -45.8 0.984   1.039 1.037 0.002 1.002   51.01 14.54 36.47 3.508
8 A A   2876 2910 -33.6 0.988   1.036 1.033 0.003 1.003   24.94 42.53 -17.59 0.586
9 A A   1702 1651 50.7 1.031   5.323 5.373 -0.050 0.991   117.07 68.12 48.95 1.719
10 A A   1493 1483 9.4 1.006   1.049 1.051 -0.002 0.998   5.90 4.78 1.12 1.233
11 A A   1486 1476 10.6 1.007   1.069 1.060 0.009 1.008   7.05 10.55 -3.51 0.668
12 A A   1474 1464 9.8 1.007   1.089 1.060 0.029 1.028   5.79 10.26 -4.47 0.564
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.