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Compare vibrational frequencies for two calculations for CH2CHO (Vinyloxy radical)


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

scale factors=0.8985, 0.943 -8.929 2.947 0.620 -0.234 -0.174
  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'   3101 3181 -80.0 0.975   1.121 1.122 -0.001 0.999   5.87 1.44 4.061
2 A' A'   3004 3059 -54.9 0.982   1.054 1.051 0.003 1.003   4.89 2.11 2.315
3 A' A'   2919 2818 101.6 1.036   1.086 1.089 -0.003 0.997   66.89 116.61 0.574
4 A' A'   1450 1825 -374.4 0.795   1.277 10.207 0.125   10.39 305.54 0.034
5 A' A'   1400 1424 -23.8 0.983   1.259 1.218 0.041 1.034   6.86 13.90 0.493
6 A' A'   1272 1386 -114.2 0.918   4.091 1.144 3.576   15.01 7.31 2.054
7 A' A'   1096 1094 2.0 1.002   3.096 2.475 1.251   16.12 57.76 0.279
8 A' A'   953 911 42.3 1.046   1.789 2.023 0.884   3.00 9.79 0.307
9 A' A'   485 482 3.7 1.008   2.452 2.386 0.066 1.028   15.02 15.59 0.964
10 A" A"   915 1016 -100.9 0.901   1.496 1.670 0.896   0.06 5.85 0.011
11 A" A"   709 634 75.0 1.118   1.259 1.243 0.016 1.013   47.17 46.14 1.022
12 A" A"   477 350 127.7 1.365   1.212 1.151 0.060 1.053   0.84 1.16 0.722
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.