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

Compare vibrational frequencies in CCCBDB for C4N2 (2-Butynedinitrile)

HF/6-31+G**

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Σg 2430 140 Σg 2290  
2 Σg 2230 111 Σg 2119  
3 Σg 576 -116 Σg 692  
4 Σu 2374 133 Σu 2241  
5 Σu 1100 -54 Σu 1154  
6 Πg 610 106 Πg 504  
7 Πg 297 34 Πg 263  
8 Πu 524 52 Πu 472  
9 Πu 117 10 Πu 107  
The calculated vibrational frequencies were scaled by 0.9042

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.