Abstract The geometric-arithmetic index of a graph G is defined as . Recently, Ghorbani et. al. introduced the eccentric version of the geometric-arithmetic index as , where is the eccentricity of the vertex u. In this paper, we compute the fourth geometric-version of Polycyclic aromatic hydrocarbons (PAHk).
Keywords Geometric-arithmetic, Topological indices, Zagreb indices, Polycyclic Aromatic Hydrocarbons.