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

Compare vibrational frequencies for two calculations for CH3CSCH3 (Thioacetone)

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 A1 A1   2997 3044 -47.3 0.984   1.100 1.102 -0.002 0.998   4.06 2.31 1.74 1.752
2 A1 A1   2877 2918 -41.0 0.986   1.041 1.038 0.003 1.003   29.78 13.32 16.46 2.236
3 A1 A1   1471 1467 4.1 1.003   1.113 1.098 0.015 1.014   0.49 1.42 -0.93 0.347
4 A1 A1   1399 1375 23.8 1.017   1.213 1.224 -0.010 0.991   3.50 5.77 -2.27 0.606
5 A1 A1   1277 1285 -7.6 0.994   3.271 3.718 -0.447 0.880   172.56 73.98 98.58 2.332
6 A1 A1   1002 997 4.5 1.004   1.705 1.653 0.051 1.031   15.81 0.09 15.72 173.004
7 A1 A1   676 689 -12.8 0.981   4.507 4.459 0.048 1.011   5.52 0.24 5.29 23.438
8 A1 A1   360 362 -2.1 0.994   2.492 2.433 0.059 1.024   1.08 0.24 0.85 4.584
9 A2 A2   2914 2982 -67.9 0.977   1.100 1.100 -0.000 1.000   0.00 0.00 0.00  
10 A2 A2   1448 1441 7.5 1.005   1.051 1.053 -0.002 0.998   0.00 0.00 0.00  
11 A2 A2   912 904 8.1 1.009   1.210 1.206 0.003 1.003   0.00 0.00 0.00  
12 A2 A2   71 96 -24.7 0.743   1.019 1.021 -0.002 0.998   0.00 0.00 0.00  
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.