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

Compare vibrational frequencies in CCCBDB for CH3CCH (propyne)

MP2/3-21G

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 A1 3329 -5 A1 3334  
2 A1 2945 27 A1 2918  
3 A1 2045 -79 A1 2124  
4 A1 1432 50 A1 1382  
5 A1 857 -74 A1 931  
6 E 3007 -1 E 3008  
7 E 1517 65 E 1452  
8 E 1071 18 E 1053  
9 E 570 -63 E 633  
10 E 235 -93 E 328  
The calculated vibrational frequencies were scaled by 0.9545

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.