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

Compare vibrational frequencies in CCCBDB for CH3COOH (Acetic acid)

mPW1PW91/3-21G

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 A' 3393 -190 A' 3583  
2 A' 3073 22 A' 3051  
3 A' 2961 17 A' 2944  
4 A' 1744 -44 A' 1788  
5 A' 1461 31 A' 1430  
6 A' 1384 2 A' 1382  
7 A' 1330 66 A' 1264  
8 A' 1136 -46 A' 1182  
9 A' 966 -23 A' 989  
10 A' 820 -27 A' 847  
11 A' 545 -112 A' 657  
12 A' 390   A'   questionable (581 listed)
13 A" 3024 28 A" 2996  
14 A" 1473 43 A" 1430  
15 A" 1060 12 A" 1048  
16 A" 652 10 A" 642  
17 A" 535 1 A" 534  
18 A" 92 -1 A" 93  
The calculated vibrational frequencies were scaled by 0.9546

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.