The eccentric connectivity polynomial of two classes of nanotubes

In theoretical chemistry, the eccentric connectivity index xi(G) of a molecular graph G was introduced as xi(G) = Sigma(nu is an element of V(G)) d(v)epsilon(v) where d(v) expresses the degree of vertex v and epsilon(v) is the largest distance between v and any other vertex of G. The corresponding eccentric connectivity polynomial is denoted by xi(G, x) = Sigma(nu is an element of V(G)) d(v) chi(delta(v)) (G) (G,x). In this paper, we present the exact expressions of eccentric connectivity polynomial for V-phenylenic nanotubes and ZigZag polyhex nanotubes. (C) 2015 Elsevier Ltd. All rights reserved.