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

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

MP2/3-21G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 3045 27 Ag 3018  
2 Ag 2951 21 Ag 2930  
3 Ag 1564 -155 Ag 1719  
4 Ag 1474 50 Ag 1424  
5 Ag 1402 36 Ag 1366  
6 Ag 1205 -69 Ag 1274  
7 Ag 981 -23 Ag 1004  
8 Ag 628 -57 Ag 685  
9 Ag 518 -96 Ag 614  
10 Ag 356 -13 Ag 369  
11 Au 3016 26 Au 2990  
12 Au 1496 75 Au 1421  
13 Au 993 -118 Au 1111  
14 Au 368 29 Au 339  
15 Au 120        
16 Au 70 22 Au 48  
17 Bg 3016 38 Bg 2978  
18 Bg 1499 75 Bg 1424  
19 Bg 1077 -32 Bg 1109  
20 Bg 644 106 Bg 538  
21 Bg 94 -146 Bg 240  
22 Bu 3045 34 Bu 3011  
23 Bu 2951 25 Bu 2926  
24 Bu 1553 -165 Bu 1718  
25 Bu 1478 57 Bu 1421  
26 Bu 1401 48 Bu 1353  
27 Bu 1109 -2 Bu 1111  
28 Bu 869 -58 Bu 927  
29 Bu 507 -27 Bu 534  
30 Bu 233 -17 Bu 250  
The calculated vibrational frequencies were scaled by 0.9513

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.