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Compare vibrational frequencies for two calculations for H2ONH3 (Water Ammonia Dimer)


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

scale factors=0.8985, 0.943 -0.585 0.102
  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'   3728 3651 77.7 1.021   1.075 1.072 0.003 1.003   82.81 60.48 1.369
2 A' A'   3564 3451 113.6 1.033   1.054 1.090 -0.036 0.967   315.89 7.03 44.964
3 A' A'   3436 3417 18.7 1.005   1.091 1.055 0.036 1.034   5.14 391.76 0.013
4 A' A'   3318 3307 11.3 1.003   1.027 1.027 0.000 1.000   3.58 7.03 0.510
5 A' A'   1678 1686 -8.0 0.995   1.076 1.075 0.001 1.001   94.53 75.56 1.251
6 A' A'   1659 1650 8.7 1.005   1.066 1.065 0.001 1.001   34.00 31.92 1.065
7 A' A'   1126 1130 -3.9 0.997   1.183 1.185 -0.002 0.998   204.81 166.85 1.227
8 A' A'   383 435 -52.6 0.879   1.074 1.077 -0.004 0.997   124.69 117.06 1.065
9 A' A'   166 198 -31.7 0.840   2.662 3.247 0.820   19.31 14.53 1.329
10 A' A'   144 162 -18.0 0.889   1.306 1.204 1.084   46.77 52.74 0.887
11 A" A"   3437 3451 -13.6 0.996   1.091 1.090 0.001 1.001   6.12 7.86 0.778
12 A" A"   1656 1647 9.7 1.006   1.065 1.063 0.001 1.001   25.11 23.87 1.052
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.