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Compare vibrational frequencies for two calculations for C2H2O4 (Oxalic Acid)


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

scale factors=0.8985, 0.943 -0.641 2.043 -6.806 4.817 1.598 0.618 -10.055 1.093 7.538 -0.187
  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 Ag Ag   3641 3393 247.2 1.073   1.066 1.064 0.002 1.002   0.00 0.00  
2 Ag Ag   1877 1733 144.2 1.083   10.758 11.400 0.944   0.00 0.00  
3 Ag Ag   1430 1413 16.8 1.012   5.136 3.093 1.660   0.00 0.00  
4 Ag Ag   1223 1183 40.4 1.034   1.668 1.682 -0.014 0.991   0.00 0.00  
5 Ag Ag   790 789 0.7 1.001   3.777 10.583 0.357   0.00 0.00  
6 Ag Ag   522 540 -17.9 0.967   13.035 8.219 1.586   0.00 0.00  
7 Ag Ag   418 396 22.8 1.058   8.537 6.938 1.230   0.00 0.00  
8 Au Au   646 679 -33.1 0.951   1.683 1.065 1.580   371.40 232.45 1.598
9 Au Au   417 427 -9.5 0.978   2.304 12.359 0.186   17.40 60.96 0.285
10 Au Au   8i 120 -128.3 -0.066   11.976 10.883 1.100   4.57 5.19 0.882
11 Bg Bg   830 736 94.3 1.128   11.898 4.360 2.729   0.00 0.00  
12 Bg Bg   583 659 -76.3 0.884   1.112 1.299 0.856   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.