National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 18October 2016
NIST Standard Reference Database 101
IIntroduction
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
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XIII Vibrations
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XVEntropy data
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XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers
XXIOddities

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

Compare vibrational frequencies for two calculations for AlH3+ (aluminum trihydride cation)

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 ?a A1   2923 1966 956.4 1.486   1.106 1.008 0.097 1.097   30025.58 0.03 30025.55 1154830.000
2 ?a A1   1603 569 1034.1 2.817   1.008 1.052 -0.044 0.958   4.04 160.63 -156.59 0.025
3 ?a A1   1402 257 1145.3 5.453   1.048 1.066 -0.018 0.983   578.63 82.53 496.11 7.011
4 ?a B1   776 540 236.4 1.438   1.017 1.086 -0.070 0.936   746.09 158.34 587.75 4.712
5 ?a B2   689 2055 -1365.8 0.335   1.070 1.080 -0.009 0.991   37.21 6.12 31.10 6.083
6 A2" B2   442 287 155.5 1.542   1.116 1.026 0.090 1.088   87.38 0.00 87.38 34953.040
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.