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

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

B3PW91/6-311G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3051 33 Ag 3018  
2 Ag 2943 13 Ag 2930  
3 Ag 1745 26 Ag 1719  
4 Ag 1414 -10 Ag 1424  
5 Ag 1351 -15 Ag 1366  
6 Ag 1239 -35 Ag 1274  
7 Ag 978 -26 Ag 1004  
8 Ag 666 -19 Ag 685  
9 Ag 506 -108 Ag 614  
10 Ag 347 -22 Ag 369  
11 Au 3004 14 Au 2990  
12 Au 1413 -8 Au 1421  
13 Au 924 -187 Au 1111  
14 Au 338 -1 Au 339  
15 Au 107        
16 Au 51 3 Au 48  
17 Bg 3004 26 Bg 2978  
18 Bg 1418 -6 Bg 1424  
19 Bg 1033 -76 Bg 1109  
20 Bg 605 67 Bg 538  
21 Bg 102 -138 Bg 240  
22 Bu 3051 40 Bu 3011  
23 Bu 2943 17 Bu 2926  
24 Bu 1745 27 Bu 1718  
25 Bu 1415 -6 Bu 1421  
26 Bu 1343 -10 Bu 1353  
27 Bu 1097 -14 Bu 1111  
28 Bu 885 -42 Bu 927  
29 Bu 524 -10 Bu 534  
30 Bu 228 -22 Bu 250  
The calculated vibrational frequencies were scaled by 0.9627

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.