Naslov (eng)

(n, m)-type approximations for total π-electron energy of benzenoid hydrocarbons

Autor

Soldatović, Tanja
Gutman, Ivan

Opis (eng)

Abstract In the half-century long research of the structure-dependency of the total x-electron energy (E) of benzenoid hydrocarbons (as calculated within the Hückel molecular orbital model) a large number (over 40) of (n, m)-type approximate formulas for E were put forward. These formulas (denoted here by E*) depend on only two parameters: n the number of carbon atoms (= number of vertices of the molecular graph) and m- the number of carbon- carbon bonds (= number of edges of the molecular graph). We provide here a complete list thereof (published until the middle of 2000) and report statistical data indicating the accuracy of the approximation E≈ a E* + b, with coefficients a and b determined by least-squares fitting. The best (n, m)-type formulas of this kind are capable of reproducing E with an average relative error of 0.30%. There are several such formulas, the McClelland expression → E*= √2mn (designed already in 1971) having the simplest algebraic form. It seems that 0.30% is the limit of the accuracy for the (n, m)-type approximations for total л-electron energy.

Jezik

engleski

Datum

2001

Licenca

© All rights reserved

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