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

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

QCISD/6-311G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3032 14 Ag 3018  
2 Ag 2929 -1 Ag 2930  
3 Ag 1744 25 Ag 1719  
4 Ag 1431 7 Ag 1424  
5 Ag 1376 10 Ag 1366  
6 Ag 1267 -7 Ag 1274  
7 Ag 990 -14 Ag 1004  
8 Ag 675 -10 Ag 685  
9 Ag 513 -101 Ag 614  
10 Ag 351 -18 Ag 369  
11 Au 2996 6 Au 2990  
12 Au 1428 7 Au 1421  
13 Au 945 -166 Au 1111  
14 Au 340 1 Au 339  
15 Au 121        
16 Au 53 5 Au 48  
17 Bg 2996 18 Bg 2978  
18 Bg 1432 8 Bg 1424  
19 Bg 1042 -67 Bg 1109  
20 Bg 601 63 Bg 538  
21 Bg 121 -119 Bg 240  
22 Bu 3032 21 Bu 3011  
23 Bu 2929 3 Bu 2926  
24 Bu 1727 9 Bu 1718  
25 Bu 1431 10 Bu 1421  
26 Bu 1367 14 Bu 1353  
27 Bu 1109 -2 Bu 1111  
28 Bu 896 -31 Bu 927  
29 Bu 525 -9 Bu 534  
30 Bu 232 -18 Bu 250  
The calculated vibrational frequencies were scaled by 0.9574

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.