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

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

MP2/CEP-31G

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3074 56 Ag 3018  
2 Ag 2946 16 Ag 2930  
3 Ag 1511 -208 Ag 1719  
4 Ag 1437 13 Ag 1424  
5 Ag 1400 34 Ag 1366  
6 Ag 1272 -2 Ag 1274  
7 Ag 998 -6 Ag 1004  
8 Ag 662 -23 Ag 685  
9 Ag 503 -111 Ag 614  
10 Ag 341 -28 Ag 369  
11 Au 3044 54 Au 2990  
12 Au 1440 19 Au 1421  
13 Au 989 -122 Au 1111  
14 Au 340 1 Au 339  
15 Au 104        
16 Au 62 14 Au 48  
17 Bg 3043 65 Bg 2978  
18 Bg 1443 19 Bg 1424  
19 Bg 1062 -47 Bg 1109  
20 Bg 585 47 Bg 538  
21 Bg 103 -137 Bg 240  
22 Bu 3074 63 Bu 3011  
23 Bu 2946 20 Bu 2926  
24 Bu 1503 -215 Bu 1718  
25 Bu 1442 21 Bu 1421  
26 Bu 1399 46 Bu 1353  
27 Bu 1121 10 Bu 1111  
28 Bu 910 -17 Bu 927  
29 Bu 508 -26 Bu 534  
30 Bu 221 -29 Bu 250  
The calculated vibrational frequencies were scaled by 0.9663

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.