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

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

QCISD/6-31G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3042 24 Ag 3018  
2 Ag 2938 8 Ag 2930  
3 Ag 1740 21 Ag 1719  
4 Ag 1441 17 Ag 1424  
5 Ag 1383 17 Ag 1366  
6 Ag 1282 8 Ag 1274  
7 Ag 994 -10 Ag 1004  
8 Ag 678 -7 Ag 685  
9 Ag 513 -101 Ag 614  
10 Ag 353 -16 Ag 369  
11 Au 3007 17 Au 2990  
12 Au 1440 19 Au 1421  
13 Au 951 -160 Au 1111  
14 Au 336 -3 Au 339  
15 Au 120        
16 Au 56 8 Au 48  
17 Bg 3007 29 Bg 2978  
18 Bg 1443 19 Bg 1424  
19 Bg 1040 -69 Bg 1109  
20 Bg 596 58 Bg 538  
21 Bg 121 -119 Bg 240  
22 Bu 3042 31 Bu 3011  
23 Bu 2938 12 Bu 2926  
24 Bu 1721 3 Bu 1718  
25 Bu 1441 20 Bu 1421  
26 Bu 1374 21 Bu 1353  
27 Bu 1115 4 Bu 1111  
28 Bu 902 -25 Bu 927  
29 Bu 522 -12 Bu 534  
30 Bu 232 -18 Bu 250  
The calculated vibrational frequencies were scaled by 0.9523

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.