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
VIInput and output files
VIITutorials and Units
VIIILinks to other sites
IXFeedback
XOlder CCCBDB versions
XIIGeometries
XIII Vibrations
XIVReaction data
XVEntropy data
XVIBibliographic data
XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers
XXIOddities

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IV.C.1. (XIII.D.1.)

Compare vibrational frequencies in CCCBDB for C3H4N2 (1H-Imidazole)

mPW1PW91/STO-3G

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 A' 3361 -156 A' 3517  
2 A' 3142 -1 A' 3143  
3 A' 3112 -11 A' 3123  
4 A' 3112 2 A' 3110  
5 A' 1460 12 A' 1448  
6 A' 1412 8 A' 1404  
7 A' 1364 36 A' 1328  
8 A' 1261 -4 A' 1265  
9 A' 1149 -39 A' 1188  
10 A' 1060 -38 A' 1098  
11 A' 1043 -19 A' 1062  
12 A' 1007 -6 A' 1013  
13 A' 982 -6 A' 988  
14 A' 843 -80 A' 923  
15 A' 811 -87 A' 898  
16 A" 811 -20 A" 831  
17 A" 726 -32 A" 758  
18 A" 694 20 A" 674  
19 A" 588 -75 A" 663  
20 A" 572 -49 A" 621  
21 A" 426 -113 A" 539  
The calculated vibrational frequencies were scaled by 0.8789

See section XIII.C.3 List or set vibrational scaling factors to change the scale factors used here.
See section III.B.3.c Calculate a vibrational scaling factor for a set of molecules to determine the least squares best scaling factor.
See section III.B.3.b List of vibrational scaling factors and their uncertainties for information on where the above scaling factor is from.