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

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

B3PW91/6-31G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3054 36 Ag 3018  
2 Ag 2941 11 Ag 2930  
3 Ag 1749 30 Ag 1719  
4 Ag 1414 -10 Ag 1424  
5 Ag 1354 -12 Ag 1366  
6 Ag 1245 -29 Ag 1274  
7 Ag 977 -27 Ag 1004  
8 Ag 666 -19 Ag 685  
9 Ag 503 -111 Ag 614  
10 Ag 346 -23 Ag 369  
11 Au 3006 16 Au 2990  
12 Au 1417 -4 Au 1421  
13 Au 923 -188 Au 1111  
14 Au 333 -6 Au 339  
15 Au 109        
16 Au 53 5 Au 48  
17 Bg 3006 28 Bg 2978  
18 Bg 1422 -2 Bg 1424  
19 Bg 1027 -82 Bg 1109  
20 Bg 598 60 Bg 538  
21 Bg 105 -135 Bg 240  
22 Bu 3054 43 Bu 3011  
23 Bu 2941 15 Bu 2926  
24 Bu 1748 30 Bu 1718  
25 Bu 1415 -6 Bu 1421  
26 Bu 1346 -7 Bu 1353  
27 Bu 1096 -15 Bu 1111  
28 Bu 885 -42 Bu 927  
29 Bu 518 -16 Bu 534  
30 Bu 226 -24 Bu 250  
The calculated vibrational frequencies were scaled by 0.9567

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.