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

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

mPW1PW91/6-31G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3046 28 Ag 3018  
2 Ag 2933 3 Ag 2930  
3 Ag 1755 36 Ag 1719  
4 Ag 1409 -15 Ag 1424  
5 Ag 1353 -13 Ag 1366  
6 Ag 1247 -27 Ag 1274  
7 Ag 975 -29 Ag 1004  
8 Ag 667 -18 Ag 685  
9 Ag 504 -110 Ag 614  
10 Ag 345 -24 Ag 369  
11 Au 2999 9 Au 2990  
12 Au 1412 -9 Au 1421  
13 Au 921 -190 Au 1111  
14 Au 333 -6 Au 339  
15 Au 108        
16 Au 54 6 Au 48  
17 Bg 2999 21 Bg 2978  
18 Bg 1417 -7 Bg 1424  
19 Bg 1026 -83 Bg 1109  
20 Bg 597 59 Bg 538  
21 Bg 104 -136 Bg 240  
22 Bu 3047 36 Bu 3011  
23 Bu 2933 7 Bu 2926  
24 Bu 1752 34 Bu 1718  
25 Bu 1410 -11 Bu 1421  
26 Bu 1343 -10 Bu 1353  
27 Bu 1094 -17 Bu 1111  
28 Bu 885 -42 Bu 927  
29 Bu 516 -18 Bu 534  
30 Bu 226 -24 Bu 250  
The calculated vibrational frequencies were scaled by 0.9483

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.