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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 3012 -51 A1 3063  
2 A1 2978 -65 A1 3043  
3 A1 1476 -96 A1 1572  
4 A1 1335 -79 A1 1414  
5 A1 1132 -151 A1 1283  
6 A1 1060 -100 A1 1160  
7 A1 976 -87 A1 1063  
8 A1 794 -170 A1 964  
9 A1 637 18 A1 619  
10 A2 970 34 A2 936  
11 A2 889 26 A2 863  
12 A2 723 -28 A2 751  
13 A2 325 -96 A2 421  
14 B1 931   B1   760 reassinged to mode 15
15 B1 713 -47 B1 760 696 questionable
16 B1 329 -41 B1 370  
17 B2 2996 -79 B2 3075  
18 B2 2974 -69 B2 3043  
19 B2 1441 -124 B2 1565  
20 B2 1335 -109 B2 1444  
21 B2 1208 -31 B2 1239  
22 B2 1006 -46 B2 1052  
23 B2 959 -50 B2 1009  
24 B2 589 -75 B2 664  
The calculated vibrational frequencies were scaled by 0.9535

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.