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

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

B2PLYP/6-31G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3047 29 Ag 3018  
2 Ag 2940 10 Ag 2930  
3 Ag 1698 -21 Ag 1719  
4 Ag 1430 6 Ag 1424  
5 Ag 1366 -0 Ag 1366  
6 Ag 1253 -21 Ag 1274  
7 Ag 982 -22 Ag 1004  
8 Ag 664 -21 Ag 685  
9 Ag 503 -111 Ag 614  
10 Ag 348 -21 Ag 369  
11 Au 3004 14 Au 2990  
12 Au 1433 12 Au 1421  
13 Au 938 -173 Au 1111  
14 Au 332 -7 Au 339  
15 Au 113        
16 Au 57 9 Au 48  
17 Bg 3004 26 Bg 2978  
18 Bg 1437 13 Bg 1424  
19 Bg 1033 -76 Bg 1109  
20 Bg 595 57 Bg 538  
21 Bg 112 -128 Bg 240  
22 Bu 3047 36 Bu 3011  
23 Bu 2940 14 Bu 2926  
24 Bu 1693 -25 Bu 1718  
25 Bu 1431 10 Bu 1421  
26 Bu 1360 7 Bu 1353  
27 Bu 1101 -10 Bu 1111  
28 Bu 885 -42 Bu 927  
29 Bu 516 -18 Bu 534  
30 Bu 229 -21 Bu 250  
The calculated vibrational frequencies were scaled by 0.9492

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.