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

Compare vibrational frequencies in CCCBDB for C4H6O2 (2,3-Butanedione)

B3LYP/CEP-31G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3062 44 Ag 3018  
2 Ag 2956 26 Ag 2930  
3 Ag 1724 5 Ag 1719  
4 Ag 1407 -17 Ag 1424  
5 Ag 1353 -13 Ag 1366  
6 Ag 1236 -38 Ag 1274  
7 Ag 969 -35 Ag 1004  
8 Ag 656 -29 Ag 685  
9 Ag 493 -121 Ag 614  
10 Ag 338 -31 Ag 369  
11 Au 3019 29 Au 2990  
12 Au 1408 -13 Au 1421  
13 Au 923 -188 Au 1111  
14 Au 340 1 Au 339  
15 Au 110        
16 Au 55 7 Au 48  
17 Bg 3019 41 Bg 2978  
18 Bg 1413 -11 Bg 1424  
19 Bg 1023 -86 Bg 1109  
20 Bg 593 55 Bg 538  
21 Bg 108 -132 Bg 240  
22 Bu 3062 51 Bu 3011  
23 Bu 2956 30 Bu 2926  
24 Bu 1718 0 Bu 1718  
25 Bu 1408 -13 Bu 1421  
26 Bu 1342 -11 Bu 1353  
27 Bu 1082 -29 Bu 1111  
28 Bu 877 -50 Bu 927  
29 Bu 511 -23 Bu 534  
30 Bu 222 -28 Bu 250  
The calculated vibrational frequencies were scaled by 0.9657

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.