Abstract
Let G = (V, E) be a connected graph. The eccentric connectivity index of G is defined by xi(C) (G) = Sigma(u)(is an element of V)((G)) deg(u)e(u), where deg(u) and e(u) denote the degree and eccentricity of the vertex u in G, respectively. In this paper, we introduce a new formulation of xi(C) that will be called the distance eccentric connectivity index of G and defined by
xi(De)(G) = Sigma(u is an element of V(G))deg(De)(u)e(u)
where deg(De)(u) denotes the distance eccentricity degree of the vertex u in G. The aim of this paper is to introduce and study this new topological index. The values of the eccentric connectivity index is calculated for some fundamental graph classes and also for some graph operations. Some inequalities giving upper and lower bounds for this index are obtained.