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

Compare vibrational frequencies for two calculations for NO3- (nitrate anion)

A = HF/6-31G*

B = MP2FC/6-31G*

  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'   1249 841 408.3 1.486   15.995 15.995 0.000 1.000   0.00 0.00 0.00  
2 A2" A2"   785 580 204.7 1.353   14.408 14.408 0.000 1.000   28.23 0.36 27.87 77.455
3 E' E'   861 9587 -8725.8 0.090   15.964 14.428 1.536 1.106   93.38 0.00 93.38  
4 E' E'   1978i 535 -2513.0 -3.699   14.434 15.971 -1.537 0.904   4245.31 65.54 4179.78 64.778
5 B2 E'   1720 535 1185.6 3.217   14.620 15.971 -1.351 0.915   831.62 65.54 766.09 12.690
6 B2 E'   521 535 -14.1 0.974   15.746 15.971 -0.225 0.986   10.83 65.54 -54.70 0.165
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.