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

Compare vibrational frequencies in CCCBDB for C4H6 (Cyclobutene)

PM3

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1   -3060 A1 3060  
2   -2935 A1 2935  
3   -1570 A1 1570  
4   -1450 A1 1450  
5   -1276 A1 1276  
6   -1186 A1 1186  
7   -1113 A1 1113  
8   -886 A1 886  
9   -2955 A2 2955  
10   -1276 A2 1276  
11   -1081 A2 1081  
12   -850 A2 850  
13   -325 A2 325  
14   -2955 B1 2955  
15   -1074 B1 1074  
16   -846 B1 846  
17   -635 B1 635  
18   -3047 B2 3047  
19   -2916 B2 2916  
20   -1427 B2 1427  
21   -1294 B2 1294  
22   -1214 B2 1214  
23   -888 B2 888  
24   -740 B2 740  
The calculated vibrational frequencies were scaled by 0.974

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.