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

Compare vibrational frequencies in CCCBDB for CH3CH(CH3)CH3 (Isobutane)

PM3

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1   -2962 A1 2962  
2   -2904 A1 2904  
3   -2880 A1 2880  
4   -1477 A1 1477  
5   -1394 A1 1394  
6   -1177 A1 1177  
7   -797 A1 797  
8   -426 A1 426  
9   -2962 A2 2962  
10   -1475 A2 1475  
11   -966 A2 966  
12   -198 A2 198  
13   -2962 E 2962  
14   -2962 E 2962  
15   -2894 E 2894  
16   -1477 E 1477  
17   -1475 E 1475  
18   -1371 E 1371  
19   -1330 E 1330  
20   -1166 E 1166  
21   -966 E 966  
22   -918 E 918  
23   -367 E 367  
24     E    
The calculated vibrational frequencies were scaled by 0.974

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.