National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 19April 2018
NIST Standard Reference Database 101
IIntroduction
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
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IXFeedback
XOlder CCCBDB versions
XIIGeometries
XIII Vibrations
XIVReaction data
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 C2H5Br (Ethyl bromide)

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' A'   2967 3018 -51.2 0.983   1.060 1.099 -0.039 0.965   33.39 13.49 19.91 2.476
2 A' A'   2944 2988 -43.6 0.985   1.094 1.059 0.034 1.032   10.31 8.52 1.79 1.210
3 A' A'   2884 2933 -49.8 0.983   1.041 1.038 0.004 1.004   28.53 13.27 15.26 2.150
4 A' A'   1475 1473 2.3 1.002   1.056 1.049 0.007 1.006   1.41 2.90 -1.49 0.486
5 A' A'   1471 1462 9.7 1.007   1.102 1.102 -0.000 1.000   1.34 1.24 0.11 1.087
6 A' A'   1406 1387 18.6 1.013   1.232 1.240 -0.008 0.993   2.43 6.01 -3.58 0.405
7 A' A'   1271 1255 15.9 1.013   1.250 1.267 -0.017 0.987   83.78 55.26 28.52 1.516
8 A' A'   1053 1057 -4.8 0.995   1.807 2.187 -0.380 0.826   0.82 0.23 0.60 3.650
9 A' A'   941 955 -13.6 0.986   1.931 1.633 0.298 1.182   12.33 12.03 0.30 1.025
10 A' A'   540 560 -20.3 0.964   4.155 4.045 0.110 1.027   31.00 13.12 17.88 2.363
11 A' A'   278 282 -3.5 0.988   3.251 3.200 0.052 1.016   2.67 1.99 0.69 1.346
12 A" A"   3026 3060 -34.2 0.989   1.113 1.111 0.002 1.002   12.17 8.73 3.44 1.394
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.