文摘
The augmented Zagreb index of a graph G is defined as $$ \operatorname{AZI}(G)=\sum_{uv\in E(G)} \biggl( \frac{d_{u}d_{v}}{d_{u}+d_{v}-2} \biggr)^{3}, $$ where \(E(G)\) is the edge set, and \(d_{u}\) , \(d_{v}\) are the degrees of vertices u and v in G, respectively. This new molecular structure descriptor, introduced by Furtula et al. (J.?Math. Chem. 48:370-380, 2010), has proven to be a valuable predictive index in the study of the heat of formation in heptanes and octanes. In this paper, the n-vertex unicyclic graphs with the minimal and the second minimal AZI indices and the n-vertex bicyclic graphs with the minimal AZI index are determined.