National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
IIntroduction
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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 N(CH3)2CONH2 (Urea, N,N-dimethyl-)

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   3541 3491 50.5 1.014   1.101 1.098 0.003 1.003   38.91 27.59 11.32 1.410
2 A A   3440 3381 58.2 1.017   1.049 1.048 0.000 1.000   37.74 26.70 11.04 1.413
3 A A   3029 3065 -36.6 0.988   1.097 1.099 -0.002 0.998   4.50 0.10 4.40 46.082
4 A A   2977 3035 -57.2 0.981   1.099 1.103 -0.004 0.996   29.26 6.60 22.66 4.431
5 A A   2932 2983 -51.0 0.983   1.097 1.095 0.002 1.002   44.71 8.14 36.57 5.491
6 A A   2924 2976 -51.7 0.983   1.106 1.104 0.002 1.001   56.21 49.79 6.42 1.129
7 A A   2880 2913 -33.2 0.989   1.042 1.037 0.005 1.005   37.52 56.59 -19.07 0.663
8 A A   2871 2896 -24.4 0.992   1.045 1.045 0.000 1.000   78.65 51.19 27.47 1.537
9 A A   1751 1714 36.3 1.021   6.837 6.683 0.154 1.023   520.67 359.78 160.89 1.447
10 A A   1625 1587 38.2 1.024   1.231 1.208 0.024 1.020   168.26 143.44 24.82 1.173
11 A A   1506 1505 0.9 1.001   1.200 1.251 -0.051 0.959   84.64 49.71 34.93 1.703
12 A A   1493 1483 10.1 1.007   1.054 1.052 0.002 1.002   2.13 15.61 -13.48 0.136
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.