Bounds for Huckel Total n-Electron Energy

Various lower and upper bounds (eqs 9, 15, 16, 26, 27, 28, 34, 40 and 41 are obtained for the Hiickel total it-electron energy. There exists a rather accurate linear correlation between the bounds 16 and 26 and the Hiickel total it-electron energy (eqs 31 and 32, correlation coefficients 0.9995)

Topological Formulas for Free-Valence Index

Four topological identities (5), (6), (7) and (9) for free-valence index are derived

New Applications of the Dewar Index

It is demonstrated that the Dewar index D plays an important role also in non-perturbative MO theory. Approximate topological formulas are derived for the stability of a heteroconjugated molecule relative to its parent hydrocarbon (eq 12), the self-polarizability of an atom (eq 13) and the atom localization energy (eq 16). All three quantities are shown to depend on D. These relations hold for alternant systems only. Their numerical reliability is also studied

On the Characterization of Monocyclic Structures. Hosoya\u27s Index

The previous work by Bonchev et al.3 is complemented by an explicit general topological formula for Hosoya\u27s index of a cycle

Topological Properties of Benzenoid Systems. X. Note on a Graph-Theoretical Polynomial of Knop and Trinajstic

A new graph-theoretical polynomial T (G; x) was recently introduced by Knop and Trinajstic\u27:\u27. T (G ; x) differs from the sextet polynomial. The basic mathematical properties of T (G; x) are determined