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

Compare vibrational frequencies in CCCBDB for C4H6 (Cyclobutene)

PBEPBE/3-21G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 A1 3031 -29 A1 3060  
2 A1 2872 -63 A1 2935  
3 A1 1494 -76 A1 1570  
4 A1 1405 -45 A1 1450  
5 A1 1118 -158 A1 1276  
6 A1 1047 -139 A1 1186  
7 A1 921 -192 A1 1113  
8 A1 805 -81 A1 886  
9 A2 2915 -40 A2 2955  
10 A2 1099 -177 A2 1276  
11 A2 955 -126 A2 1081  
12 A2 876 26 A2 850  
13 A2 295 -30 A2 325  
14 B1 2930 -25 B1 2955  
15 B1 1044 -30 B1 1074  
16 B1 813 -33 B1 846  
17 B1 610 -25 B1 635  
18 B2 2995 -52 B2 3047  
19 B2 2865 -51 B2 2916  
20 B2 1391 -36 B2 1427  
21 B2 1213 -81 B2 1294  
22 B2 1153 -61 B2 1214  
23 B2 831 -57 B2 888  
24 B2 812 72 B2 740  
The calculated vibrational frequencies were scaled by 0.9535

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.