Title
Extremal benzenoid systems for two modified versions of the Randić index.
Abstract
Let G=(V,E) be a molecular graph, in which the vertices of V represent atoms and the edges of E the bonds between pairs of atoms. One of the earliest and most widely studied degree-based molecular descriptor, the Randić index of G, is defined as R(G)=∑uv∈E(dudv)−12, where du denotes the degree of u ∈ V. Bollobás and Erdős (1998) generalized this index by replacing −12 with any fixed real number. To facilitate the enumeration of these indices, motivated by earlier work of Dvořák et al. (2011) and Knor et al. (2015) introduced two other indices, that provide lower and upper bounds, respectively: Rα′(G)=∑uv∈Emin{duα,dvα} and Rα″(G)=∑uv∈Emax{duα,dvα}. In this paper, we give expressions for computing Rα′ and Rα″ of benzenoid systems and phenylenes, as well as a relation between Rα′ and Rα″ of a phenylene and its corresponding hexagonal squeeze. We also determine the extremal values of Rα′ and Rα″ in benzenoid systems with h hexagons for different intervals for the value of α.
Year
DOI
Venue
2018
10.1016/j.amc.2018.05.021
Applied Mathematics and Computation
Keywords
Field
DocType
Randić index,Generalized Randić index,Inlet,Benzenoid system,Catacondensed benzenoid system
Molecular descriptor,Molecular graph,Combinatorics,Vertex (geometry),Mathematical analysis,Hexagonal crystal system,Atom,Phenylene,Real number,Mathematics
Journal
Volume
ISSN
Citations 
337
0096-3003
0
PageRank 
References 
Authors
0.34
10
4
Name
Order
Citations
PageRank
Fengwei Li110513.73
Hajo Broersma274187.39
Juan Rada33610.02
Yuefang Sun411318.02