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

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

mPW1PW91/6-31+G**

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3053 35 Ag 3018  
2 Ag 2935 5 Ag 2930  
3 Ag 1743 24 Ag 1719  
4 Ag 1390 -34 Ag 1424  
5 Ag 1342 -24 Ag 1366  
6 Ag 1239 -35 Ag 1274  
7 Ag 969 -35 Ag 1004  
8 Ag 669 -16 Ag 685  
9 Ag 502 -112 Ag 614  
10 Ag 345 -24 Ag 369  
11 Au 3004 14 Au 2990  
12 Au 1392 -29 Au 1421  
13 Au 912 -199 Au 1111  
14 Au 336 -3 Au 339  
15 Au 102        
16 Au 44 -4 Au 48  
17 Bg 3005 27 Bg 2978  
18 Bg 1398 -26 Bg 1424  
19 Bg 1017 -92 Bg 1109  
20 Bg 592 54 Bg 538  
21 Bg 99 -141 Bg 240  
22 Bu 3054 43 Bu 3011  
23 Bu 2935 9 Bu 2926  
24 Bu 1741 23 Bu 1718  
25 Bu 1391 -30 Bu 1421  
26 Bu 1329 -24 Bu 1353  
27 Bu 1089 -22 Bu 1111  
28 Bu 884 -43 Bu 927  
29 Bu 519 -15 Bu 534  
30 Bu 225 -25 Bu 250  
The calculated vibrational frequencies were scaled by 0.9518

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.