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

Compare vibrational frequencies in CCCBDB for C2H4 (Ethylene)

MP2/CEP-31G

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3056 30 Ag 3026  
2 Ag 1593 -30 Ag 1623  
3 Ag 1316 -26 Ag 1342  
4 Au 987 -36 Au 1023  
5 B1u 3029 41 B1u 2989 sym was B3U
6 B1u 1440 -4 B1u 1444 sym was B3U
7 B2g 736 -203 B2g 940  
8 B2u 3159 54 B2u 3105  
9 B2u 786 -40 B2u 826  
10 B3g 3115 29 B3g 3086 sym was B1G
11 B3g 1174 -43 B3g 1217 sym was B1G
12 B3u 907 -42 B3u 949 sym was B1U
The calculated vibrational frequencies were scaled by 0.9663

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.