The atom bond sum connectivity (ABS) index of a graph Γ = (V (Γ), E (Γ) ) is formulated by ABS () = ₗₘ ₄ () d (ₗ) + ₃_{ (y) - 2d_{ (x) + d_ (y) }}, where dΓ (x) denotes the degree of vertex x in Γ. In this work, we determine the maximum value of atom bond sum connectivity index of chemical unicyclic graphs with a perfect matching and identify the corresponding extremal graphs. Our discoveries extend the results of the recent paper Wang et al. , MATCH Commun. Math. Comput. Chem. 92 (2024) 653-669 from chemical trees with a perfect matching to chemical unicyclic graphs with a perfect matching.
Du et al. (Wed,) studied this question.