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

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

QCISD/6-31+G**

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3055 37 Ag 3018  
2 Ag 2944 14 Ag 2930  
3 Ag 1707 -12 Ag 1719  
4 Ag 1428 4 Ag 1424  
5 Ag 1371 5 Ag 1366  
6 Ag 1265 -9 Ag 1274  
7 Ag 988 -16 Ag 1004  
8 Ag 672 -13 Ag 685  
9 Ag 505 -109 Ag 614  
10 Ag 347 -22 Ag 369  
11 Au 3018 28 Au 2990  
12 Au 1425 4 Au 1421  
13 Au 937 -174 Au 1111  
14 Au 332 -7 Au 339  
15 Au 108        
16 Au 35 -13 Au 48  
17 Bg 3018 40 Bg 2978  
18 Bg 1428 4 Bg 1424  
19 Bg 1021 -88 Bg 1109  
20 Bg 580 42 Bg 538  
21 Bg 108 -132 Bg 240  
22 Bu 3056 45 Bu 3011  
23 Bu 2944 18 Bu 2926  
24 Bu 1688 -30 Bu 1718  
25 Bu 1428 7 Bu 1421  
26 Bu 1363 10 Bu 1353  
27 Bu 1105 -6 Bu 1111  
28 Bu 894 -33 Bu 927  
29 Bu 519 -15 Bu 534  
30 Bu 227 -23 Bu 250  
The calculated vibrational frequencies were scaled by 0.9454

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.