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

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

B3PW91/3-21G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3057 39 Ag 3018  
2 Ag 2949 19 Ag 2930  
3 Ag 1687 -32 Ag 1719  
4 Ag 1442 18 Ag 1424  
5 Ag 1379 13 Ag 1366  
6 Ag 1210 -64 Ag 1274  
7 Ag 985 -19 Ag 1004  
8 Ag 647 -38 Ag 685  
9 Ag 522 -92 Ag 614  
10 Ag 361 -8 Ag 369  
11 Au 3006 16 Au 2990  
12 Au 1459 38 Au 1421  
13 Au 965 -146 Au 1111  
14 Au 375 36 Au 339  
15 Au 115        
16 Au 35 -13 Au 48  
17 Bg 3006 28 Bg 2978  
18 Bg 1465 41 Bg 1424  
19 Bg 1066 -43 Bg 1109  
20 Bg 653 115 Bg 538  
21 Bg 59 -181 Bg 240  
22 Bu 3057 46 Bu 3011  
23 Bu 2949 23 Bu 2926  
24 Bu 1683 -35 Bu 1718  
25 Bu 1445 24 Bu 1421  
26 Bu 1378 25 Bu 1353  
27 Bu 1108 -3 Bu 1111  
28 Bu 883 -44 Bu 927  
29 Bu 513 -21 Bu 534  
30 Bu 241 -9 Bu 250  
The calculated vibrational frequencies were scaled by 0.9594

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.