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

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

PBEPBE/6-31+G**

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3081 63 Ag 3018  
2 Ag 2958 28 Ag 2930  
3 Ag 1700 -19 Ag 1719  
4 Ag 1390 -34 Ag 1424  
5 Ag 1328 -38 Ag 1366  
6 Ag 1223 -51 Ag 1274  
7 Ag 964 -40 Ag 1004  
8 Ag 662 -23 Ag 685  
9 Ag 495 -119 Ag 614  
10 Ag 347 -22 Ag 369  
11 Au 3024 34 Au 2990  
12 Au 1391 -30 Au 1421  
13 Au 901 -210 Au 1111  
14 Au 328 -11 Au 339  
15 Au 100        
16 Au 45 -3 Au 48  
17 Bg 3024 46 Bg 2978  
18 Bg 1397 -27 Bg 1424  
19 Bg 1008 -101 Bg 1109  
20 Bg 589 51 Bg 538  
21 Bg 98 -142 Bg 240  
22 Bu 3082 71 Bu 3011  
23 Bu 2958 32 Bu 2926  
24 Bu 1706 -12 Bu 1718  
25 Bu 1392 -29 Bu 1421  
26 Bu 1320 -33 Bu 1353  
27 Bu 1087 -24 Bu 1111  
28 Bu 879 -48 Bu 927  
29 Bu 520 -14 Bu 534  
30 Bu 227 -23 Bu 250  
The calculated vibrational frequencies were scaled by 0.9886

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.