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

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

mPW1PW91/6-31G(2df,p)

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3054 36 Ag 3018  
2 Ag 2937 7 Ag 2930  
3 Ag 1759 40 Ag 1719  
4 Ag 1386 -38 Ag 1424  
5 Ag 1332 -34 Ag 1366  
6 Ag 1240 -34 Ag 1274  
7 Ag 966 -38 Ag 1004  
8 Ag 667 -18 Ag 685  
9 Ag 506 -108 Ag 614  
10 Ag 344 -25 Ag 369  
11 Au 3008 18 Au 2990  
12 Au 1391 -30 Au 1421  
13 Au 909 -202 Au 1111  
14 Au 337 -2 Au 339  
15 Au 109        
16 Au 50 2 Au 48  
17 Bg 3008 30 Bg 2978  
18 Bg 1396 -28 Bg 1424  
19 Bg 1026 -83 Bg 1109  
20 Bg 600 62 Bg 538  
21 Bg 101 -139 Bg 240  
22 Bu 3055 44 Bu 3011  
23 Bu 2937 11 Bu 2926  
24 Bu 1761 43 Bu 1718  
25 Bu 1386 -35 Bu 1421  
26 Bu 1320 -33 Bu 1353  
27 Bu 1088 -23 Bu 1111  
28 Bu 876 -51 Bu 927  
29 Bu 514 -20 Bu 534  
30 Bu 225 -25 Bu 250  
The calculated vibrational frequencies were scaled by 0.9547

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.