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)

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

Effect of Cycles on Topological Resonance Energy

Two basic properties of the topological resonace energy (TRE) are established: 1. TRE represents the joint effect of all cycles on total it-electron energy (E) of a conjugated system; 2. The effect of a particular cycle on TRE is equal to the effect of the same cycle on E. An approximate formula is derived, which enables one to express TRE as a linear combination of contributions of single cycles

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 Formulas for Free-Valence Index

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

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

On the Topological Resonance Energy of Heteroconjugated Molecules

It is demonstrated that the reference polynomial of a heteroconjugated :rt-electron system with arbitrary Coulomb and resonance integrals has real zeros. Some other properties of the reference polynomial are presented

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