2,405 research outputs found
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 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
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
- …