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

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

mPW1PW91/3-21G

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3059 41 Ag 3018  
2 Ag 2950 20 Ag 2930  
3 Ag 1699 -20 Ag 1719  
4 Ag 1442 18 Ag 1424  
5 Ag 1381 15 Ag 1366  
6 Ag 1218 -56 Ag 1274  
7 Ag 989 -15 Ag 1004  
8 Ag 652 -33 Ag 685  
9 Ag 525 -89 Ag 614  
10 Ag 362 -7 Ag 369  
11 Au 3009 19 Au 2990  
12 Au 1459 38 Au 1421  
13 Au 967 -144 Au 1111  
14 Au 376 37 Au 339  
15 Au 117        
16 Au 36 -12 Au 48  
17 Bg 3009 31 Bg 2978  
18 Bg 1465 41 Bg 1424  
19 Bg 1068 -41 Bg 1109  
20 Bg 655 117 Bg 538  
21 Bg 61 -179 Bg 240  
22 Bu 3059 48 Bu 3011  
23 Bu 2950 24 Bu 2926  
24 Bu 1694 -24 Bu 1718  
25 Bu 1445 24 Bu 1421  
26 Bu 1380 27 Bu 1353  
27 Bu 1111 -0 Bu 1111  
28 Bu 888 -39 Bu 927  
29 Bu 514 -20 Bu 534  
30 Bu 241 -9 Bu 250  
The calculated vibrational frequencies were scaled by 0.9546

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.