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

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

PBEPBE/6-31G**

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3079 61 Ag 3018  
2 Ag 2957 27 Ag 2930  
3 Ag 1718 -1 Ag 1719  
4 Ag 1394 -30 Ag 1424  
5 Ag 1328 -38 Ag 1366  
6 Ag 1227 -47 Ag 1274  
7 Ag 962 -42 Ag 1004  
8 Ag 660 -25 Ag 685  
9 Ag 497 -117 Ag 614  
10 Ag 346 -23 Ag 369  
11 Au 3024 34 Au 2990  
12 Au 1397 -24 Au 1421  
13 Au 899 -212 Au 1111  
14 Au 323 -16 Au 339  
15 Au 99        
16 Au 44 -4 Au 48  
17 Bg 3024 46 Bg 2978  
18 Bg 1403 -21 Bg 1424  
19 Bg 1010 -99 Bg 1109  
20 Bg 592 54 Bg 538  
21 Bg 87 -153 Bg 240  
22 Bu 3080 69 Bu 3011  
23 Bu 2957 31 Bu 2926  
24 Bu 1723 5 Bu 1718  
25 Bu 1395 -26 Bu 1421  
26 Bu 1319 -34 Bu 1353  
27 Bu 1087 -24 Bu 1111  
28 Bu 874 -53 Bu 927  
29 Bu 514 -20 Bu 534  
30 Bu 227 -23 Bu 250  
The calculated vibrational frequencies were scaled by 0.9863

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.