On the Randic and Sum-Connectivity Index of Nanotubes

Abstract

Milan Randi´ c proposed in 1975 a structural descrip- tor called the branching index that later became the well-known Randic connectivity index; it is defined on the ground of vertex degrees χ(G )= e=uv∈E(G) 1 √ dudv . In 2008, B. Zhou and N. Trinajstiproposed another connectivity index, named the Sum- connectivity index X(G).In this paper, we focus on the structure of G = VC 5C7(p, q) and H = HC5C7(p, q) nanotubes and count- ing Randiindex χ(G )= e=uv∈E(G) 1 √ d udv and sum-connectivity index X(G )= vuvv 1 √ du+dv of these nanotubes.