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

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

QCISD/3-21G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3018 0 Ag 3018  
2 Ag 2930 -0 Ag 2930  
3 Ag 1644 -75 Ag 1719  
4 Ag 1477 53 Ag 1424  
5 Ag 1403 37 Ag 1366  
6 Ag 1207 -67 Ag 1274  
7 Ag 990 -14 Ag 1004  
8 Ag 629 -56 Ag 685  
9 Ag 521 -93 Ag 614  
10 Ag 355 -14 Ag 369  
11 Au 2987 -3 Au 2990  
12 Au 1491 70 Au 1421  
13 Au 995 -116 Au 1111  
14 Au 369 30 Au 339  
15 Au 118        
16 Au 72 24 Au 48  
17 Bg 2987 9 Bg 2978  
18 Bg 1494 70 Bg 1424  
19 Bg 1076 -33 Bg 1109  
20 Bg 641 103 Bg 538  
21 Bg 97 -143 Bg 240  
22 Bu 3018 7 Bu 3011  
23 Bu 2930 4 Bu 2926  
24 Bu 1623 -95 Bu 1718  
25 Bu 1479 58 Bu 1421  
26 Bu 1403 50 Bu 1353  
27 Bu 1110 -1 Bu 1111  
28 Bu 869 -58 Bu 927  
29 Bu 510 -24 Bu 534  
30 Bu 234 -16 Bu 250  
The calculated vibrational frequencies were scaled by 0.9611

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.