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

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

HF/6-31G(2df,p)

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 2985 -33 Ag 3018  
2 Ag 2890 -40 Ag 2930  
3 Ag 1836 117 Ag 1719  
4 Ag 1427 3 Ag 1424  
5 Ag 1388 22 Ag 1366  
6 Ag 1275 1 Ag 1274  
7 Ag 1000 -4 Ag 1004  
8 Ag 672 -13 Ag 685  
9 Ag 519 -95 Ag 614  
10 Ag 349 -20 Ag 369  
11 Au 2950 -40 Au 2990  
12 Au 1434 13 Au 1421  
13 Au 958 -153 Au 1111  
14 Au 357 18 Au 339  
15 Au 129        
16 Au 54 6 Au 48  
17 Bg 2950 -28 Bg 2978  
18 Bg 1438 14 Bg 1424  
19 Bg 1072 -37 Bg 1109  
20 Bg 620 82 Bg 538  
21 Bg 129 -111 Bg 240  
22 Bu 2985 -26 Bu 3011  
23 Bu 2889 -37 Bu 2926  
24 Bu 1816 98 Bu 1718  
25 Bu 1426 5 Bu 1421  
26 Bu 1377 24 Bu 1353  
27 Bu 1110 -1 Bu 1111  
28 Bu 888 -39 Bu 927  
29 Bu 527 -7 Bu 534  
30 Bu 231 -19 Bu 250  
The calculated vibrational frequencies were scaled by 0.9055

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.