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

Compare vibrational frequencies in CCCBDB for C4H4N2 (Pyridazine)

PBEPBE/6-31G**

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 A1 3102 39 A1 3063  
2 A1 3072 29 A1 3043  
3 A1 1550 -22 A1 1572  
4 A1 1420 6 A1 1414  
5 A1 1174 -109 A1 1283  
6 A1 1122 -38 A1 1160  
7 A1 1055 -8 A1 1063  
8 A1 974 10 A1 964  
9 A1 650 31 A1 619  
10 A2 963 27 A2 936  
11 A2 897 34 A2 863  
12 A2 736 -15 A2 751  
13 A2 340 -81 A2 421  
14 B1 927   B1   760 reassinged to mode 15
15 B1 722 -38 B1 760 696 questionable
16 B1 335 -35 B1 370  
17 B2 3088 13 B2 3075  
18 B2 3068 25 B2 3043  
19 B2 1543 -22 B2 1565  
20 B2 1373 -71 B2 1444  
21 B2 1254 15 B2 1239  
22 B2 1043 -9 B2 1052  
23 B2 1006 -3 B2 1009  
24 B2 601 -63 B2 664  
The calculated vibrational frequencies were scaled by 0.9863

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.