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

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

MP3/6-31G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3033 15 Ag 3018  
2 Ag 2928 -2 Ag 2930  
3 Ag 1764 45 Ag 1719  
4 Ag 1430 6 Ag 1424  
5 Ag 1375 9 Ag 1366  
6 Ag 1278 4 Ag 1274  
7 Ag 990 -14 Ag 1004  
8 Ag 680 -5 Ag 685  
9 Ag 517 -97 Ag 614  
10 Ag 351 -18 Ag 369  
11 Au 2996 6 Au 2990  
12 Au 1428 7 Au 1421  
13 Au 945 -166 Au 1111  
14 Au 337 -2 Au 339  
15 Au 121        
16 Au 58 10 Au 48  
17 Bg 2996 18 Bg 2978  
18 Bg 1430 6 Bg 1424  
19 Bg 1034 -75 Bg 1109  
20 Bg 593 55 Bg 538  
21 Bg 122 -118 Bg 240  
22 Bu 3034 23 Bu 3011  
23 Bu 2928 2 Bu 2926  
24 Bu 1758 40 Bu 1718  
25 Bu 1430 9 Bu 1421  
26 Bu 1363 10 Bu 1353  
27 Bu 1108 -3 Bu 1111  
28 Bu 901 -26 Bu 927  
29 Bu 522 -12 Bu 534  
30 Bu 231 -19 Bu 250  
The calculated vibrational frequencies were scaled by 0.9386

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.