National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
VIInput and output files
VIITutorials and Units
VIIILinks to other sites
XOlder CCCBDB versions
XIII Vibrations
XIVReaction data
XVEntropy data
XVIBibliographic data
XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers

NIST policy on privacy, security, and accessibility.

Please rate our products
© 2013 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

The National Institute of Standards and Technology (NIST) is an agency of the U.S. Department of Commerce.

Please send questions, comments, corrections, additions and suggestions to

return to home page

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

Compare vibrational frequencies in CCCBDB for C2H4+ (Ethylene cation)


Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3003        
2 Ag 1540 52 Ag 1488  
3 Ag 1240 -19 Ag 1259  
4 Au 345 261 Au 84  
5 B1u 2994        
6 B1u 1440        
7 B2g 1097 195 B3u 901  
8 B2u 3114 2011 B2g 1103  
9 B2u 822        
10 B3g 3102 2289 B2u 813  
11 B3g 1215 -1764 B1u 2979  
12 B3u 987 -425 B1u 1412  
The calculated vibrational frequencies were scaled by 0.9042

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.