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

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

MP2=FULL/3-21G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3035 17 Ag 3018  
2 Ag 2941 11 Ag 2930  
3 Ag 1558 -161 Ag 1719  
4 Ag 1469 45 Ag 1424  
5 Ag 1397 31 Ag 1366  
6 Ag 1201 -73 Ag 1274  
7 Ag 978 -26 Ag 1004  
8 Ag 626 -59 Ag 685  
9 Ag 516 -98 Ag 614  
10 Ag 354 -15 Ag 369  
11 Au 3006 16 Au 2990  
12 Au 1491 70 Au 1421  
13 Au 989 -122 Au 1111  
14 Au 367 28 Au 339  
15 Au 120        
16 Au 70 22 Au 48  
17 Bg 3006 28 Bg 2978  
18 Bg 1494 70 Bg 1424  
19 Bg 1073 -36 Bg 1109  
20 Bg 642 104 Bg 538  
21 Bg 94 -146 Bg 240  
22 Bu 3035 24 Bu 3011  
23 Bu 2941 15 Bu 2926  
24 Bu 1548 -170 Bu 1718  
25 Bu 1473 52 Bu 1421  
26 Bu 1397 44 Bu 1353  
27 Bu 1106 -5 Bu 1111  
28 Bu 866 -61 Bu 927  
29 Bu 506 -28 Bu 534  
30 Bu 233 -17 Bu 250  
The calculated vibrational frequencies were scaled by 0.948

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.