Fulvene resonance energy

Figure 6. Comparison of resonance energies per n electron. The Hiickel results in the first column are standard and can easily be obtained from the data in Tables 2 and 3 in ref 56. The modified Pariser-Parr—Pople results in the second column are from ref 57 those in the third column are from ref 1 except for calicene, cyclobutadiene, and fulvalene which are from ref 51 and benzcyclobutadiene from ref 58. Our Hiickel results in the fourth column are from ref 56, and those in the sixth column are from ref 59. The graph theoretical results in column 5 are from ref 13. Experimental properties are from the following references calicene, refs 60—63 fulvene, ref 64 heptalene, ref 65 pentalene, refs 66 and 67 benzocyclobutadlene, ref 68 cyclobutadiene, refs 69 and 70.

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