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

Compare vibrational frequencies in CCCBDB for C4H4N2 (Pyridazine)

PBEPBE/3-21G

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 A1 3129 66 A1 3063  
2 A1 3093 50 A1 3043  
3 A1 1534 -38 A1 1572  
4 A1 1387 -27 A1 1414  
5 A1 1177 -106 A1 1283  
6 A1 1100 -60 A1 1160  
7 A1 1014 -49 A1 1063  
8 A1 826 -138 A1 964  
9 A1 662 43 A1 619  
10 A2 1009 73 A2 936  
11 A2 925 62 A2 863  
12 A2 751 0 A2 751  
13 A2 338 -83 A2 421  
14 B1 968   B1   760 reassinged to mode 15
15 B1 742 -18 B1 760 696 questionable
16 B1 343 -27 B1 370  
17 B2 3112 37 B2 3075  
18 B2 3089 46 B2 3043  
19 B2 1496 -69 B2 1565  
20 B2 1387 -57 B2 1444  
21 B2 1255 16 B2 1239  
22 B2 1045 -7 B2 1052  
23 B2 996 -13 B2 1009  
24 B2 612 -52 B2 664  
The calculated vibrational frequencies were scaled by 0.9909

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.