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

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

PBEPBE/6-31G(2df,p)

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3080 62 Ag 3018  
2 Ag 2959 29 Ag 2930  
3 Ag 1720 1 Ag 1719  
4 Ag 1384 -40 Ag 1424  
5 Ag 1316 -50 Ag 1366  
6 Ag 1224 -50 Ag 1274  
7 Ag 960 -44 Ag 1004  
8 Ag 659 -26 Ag 685  
9 Ag 498 -116 Ag 614  
10 Ag 344 -25 Ag 369  
11 Au 3025 35 Au 2990  
12 Au 1387 -34 Au 1421  
13 Au 896 -215 Au 1111  
14 Au 328 -11 Au 339  
15 Au 104        
16 Au 44 -4 Au 48  
17 Bg 3026 48 Bg 2978  
18 Bg 1393 -31 Bg 1424  
19 Bg 1015 -94 Bg 1109  
20 Bg 597 59 Bg 538  
21 Bg 91 -149 Bg 240  
22 Bu 3080 69 Bu 3011  
23 Bu 2959 33 Bu 2926  
24 Bu 1729 11 Bu 1718  
25 Bu 1384 -37 Bu 1421  
26 Bu 1308 -45 Bu 1353  
27 Bu 1084 -27 Bu 1111  
28 Bu 869 -58 Bu 927  
29 Bu 511 -23 Bu 534  
30 Bu 225 -25 Bu 250  
The calculated vibrational frequencies were scaled by 0.9897

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.