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Compare vibrational frequencies for two calculations for C8H14 (Bicyclo[2.2.2]octane)


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

scale factors=0.8985, 0.943 0.565 0.378 3.569 4.791 -0.388 -3.234 -4.965
  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   2906 2955 -48.9 0.983   1.076 1.104 -0.029 0.974   0.00 0.00  
2 A1' A1   2877 2934 -57.1 0.981   1.075 1.084 -0.010 0.991   0.00 0.00  
3 A1' A1   1507 2916 -1409.2 0.517   1.096 1.068 0.028 1.026   0.00 0.00  
4 A1' A1   1359 1493 -134.1 0.910   1.660 1.095 1.516   0.00 0.00  
5 A1' A1   995 1325 -330.2 0.751   2.069 1.691 1.224   0.00 0.00  
6 A1' A1   755 1223 -468.0 0.617   4.724 1.155 4.090   0.00 0.00  
7 A1' A1   612 1011 -398.3 0.606   6.720 1.929 3.483   0.00 0.00  
8 A1" A1   2890 904 1986.5 3.198   1.108 1.496 0.741   0.00 0.00  
9 A1" A1   1243 781 462.1 1.592   1.134 4.367 0.260   0.00 0.00  
10 A1" A1   910 610 299.8 1.491   1.432 6.396 0.224   0.00 0.00  
11 A1" A1   17i 117 -134.0 -0.142   1.733 1.747 -0.014 0.992   0.00 0.00  
12 A2' A2   2912 2969 -57.0 0.981   1.106 1.106 0.000 1.000   0.00 10.03 0.000
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.