A new version of Zagreb index of circumcoronene series of benzenoid

Among topological indices, Zagreb indices are very important, very old and they have many useful properties in chemistry and specially in mathematics chemistry. First and second Zagreb indices have been introduced by Gutman and Trinajstić as M_1(G)=\sum_{uv\in E}d_u+d_v and M_1(G)=\sum_{uv\in E}d_ud_v, where du denotes the degree of vertex u in G. Recently, we know new versions of Zagreb indices as M_1^{*}(G)=\sum_{uv\in E}ecc(u)+ecc(v), M_1^{**}(G)=\sum_{u\in V}ecc(u)^2  and M_2^{*}(G)=\sum_{uv\in E}ecc(u)ecc(v), where ecc(u) is the largest distance between u and any other vertex v of G. In this paper, we focus one of these new topological indices that we call fifth Zagreb index M_2^*(G)=M_5(G) and we compute this index for a famous molecular graph Circumcoronene series of benzenoid Hk, k≥ 1.

A new version of Zagreb index of circumcoronene series of benzenoid Keywords:

First Zagreb index , second Zagreb index , Fifth Zagreb index , Circumcoronene series of benzenoid , Cut Method , Ring-cut Method