The Geometric-Arithmetic Index of Benzenoid Systems and Phenylenes

A Note on the First Geometric-Arithmetic Index of Hexagonal Systems and Phenylenes

The first geometric-arithmetic index was introduced in the chemical theory as the summation of 2 du dv /(du  dv ) overall edges of the graph, where du stand for the degree of the vertex u. In this paper we give the expressions for computing the first geometric-arithmetic index of hexagonal systems and phenylenes and present new method for describing hexagonal system by corresponding a simple g...

On General Sum-Connectivity Index of Benzenoid Systems and Phenylenes

Randi} Index of Benzenoid Systems and Phenylenes*

A new parameter, related to and easily determined from the structure of a benzenoid system and that of a phenylene – the number of inlets (r) – is introduced. The connectivity (Randi}) index of both benzenoid systems and phenylenes is then shown to depend solely on the number of vertices and on r. A simple relation is established between the connectivity index of a phenylene and of the correspo...

The Atom-Bond Connectivity Index of Benzenoid Systems And Phenylenes

The atom-bond connectivity (ABC) index is a recently introduced topological index, defined as ABC(G) = ∑ uv∈E(G) √ du+dv−2 dudv , where du (or dv) is the degree the vertex u (or v). The ABC index of benzenoid systems and phenylenes are computed, a simple relation is established between the atom-bond connectivity index of a phenylene and the corresponding hexagonal squeeze in this paper. Mathema...

Vertex-degree-based molecular structure descriptors of benzenoid systems and phenylenes

1031 Vertex-degree-based molecular structure descriptors of benzenoid systems and phenylenes IVAN GUTMAN* and BORIS FURTULA** Faculty of Science, University of Kragujevac, P. O. Box 60, 34000 Kragujevac, Serbia (Received 12 December 2011) Abstract. Several recently published papers report expressions for various vertex-degree-based molecular structure descriptors of benzenoid systems and phenyl...