Abstract Let G=(V,E) be a simple connected molecular graph. Khadikar et.al. introduced the PI index defined by , where is the number of vertices of G lying closer to u and is the number of vertices of G lying closer to v. In this paper, we compute a closed formula of vertex PI index for Polycyclic Aromatic hydrocarbons.
Keywords Poly Aromatic Hydrocarbons PAHk ; PI index; Cut Method; Orthogonal Cut.