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

Compare vibrational frequencies in CCCBDB for CH3COOH (Acetic acid)

B3LYP/3-21G

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 A' 3349 -234 A' 3583  
2 A' 3075 24 A' 3051  
3 A' 2971 27 A' 2944  
4 A' 1734 -54 A' 1788  
5 A' 1478 48 A' 1430  
6 A' 1395 13 A' 1382  
7 A' 1326 62 A' 1264  
8 A' 1136 -46 A' 1182  
9 A' 962 -27 A' 989  
10 A' 808 -39 A' 847  
11 A' 543 -114 A' 657  
12 A' 391   A'   questionable (581 listed)
13 A" 3024 28 A" 2996  
14 A" 1489 59 A" 1430  
15 A" 1067 19 A" 1048  
16 A" 651 9 A" 642  
17 A" 533 -1 A" 534  
18 A" 88 -5 A" 93  
The calculated vibrational frequencies were scaled by 0.9649

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.