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

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

MP2=FULL/6-31G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3054 36 Ag 3018  
2 Ag 2940 10 Ag 2930  
3 Ag 1665 -54 Ag 1719  
4 Ag 1434 10 Ag 1424  
5 Ag 1370 4 Ag 1366  
6 Ag 1268 -6 Ag 1274  
7 Ag 983 -21 Ag 1004  
8 Ag 673 -12 Ag 685  
9 Ag 507 -107 Ag 614  
10 Ag 351 -18 Ag 369  
11 Au 3019 29 Au 2990  
12 Au 1436 15 Au 1421  
13 Au 941 -170 Au 1111  
14 Au 332 -7 Au 339  
15 Au 120        
16 Au 60 12 Au 48  
17 Bg 3019 41 Bg 2978  
18 Bg 1439 15 Bg 1424  
19 Bg 1031 -78 Bg 1109  
20 Bg 593 55 Bg 538  
21 Bg 121 -119 Bg 240  
22 Bu 3055 44 Bu 3011  
23 Bu 2940 14 Bu 2926  
24 Bu 1661 -57 Bu 1718  
25 Bu 1434 13 Bu 1421  
26 Bu 1362 9 Bu 1353  
27 Bu 1106 -5 Bu 1111  
28 Bu 895 -32 Bu 927  
29 Bu 515 -19 Bu 534  
30 Bu 231 -19 Bu 250  
The calculated vibrational frequencies were scaled by 0.9422

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.