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

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

CID/6-31G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3050 32 Ag 3018  
2 Ag 2946 16 Ag 2930  
3 Ag 1805 86 Ag 1719  
4 Ag 1441 17 Ag 1424  
5 Ag 1396 30 Ag 1366  
6 Ag 1291 17 Ag 1274  
7 Ag 1003 -1 Ag 1004  
8 Ag 685 0 Ag 685  
9 Ag 520 -94 Ag 614  
10 Ag 353 -16 Ag 369  
11 Au 3014 24 Au 2990  
12 Au 1442 21 Au 1421  
13 Au 957 -154 Au 1111  
14 Au 346 7 Au 339  
15 Au 122        
16 Au 54 6 Au 48  
17 Bg 3014 36 Bg 2978  
18 Bg 1445 21 Bg 1424  
19 Bg 1054 -55 Bg 1109  
20 Bg 607 69 Bg 538  
21 Bg 122 -118 Bg 240  
22 Bu 3050 39 Bu 3011  
23 Bu 2945 19 Bu 2926  
24 Bu 1788 70 Bu 1718  
25 Bu 1441 20 Bu 1421  
26 Bu 1384 31 Bu 1353  
27 Bu 1119 8 Bu 1111  
28 Bu 908 -19 Bu 927  
29 Bu 527 -7 Bu 534  
30 Bu 233 -17 Bu 250  
The calculated vibrational frequencies were scaled by 0.9237

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.