An estimation of HOMO–LUMO gap for a class of molecular graphs

Abstract For any simple connected graph G of order n , having eigen spectrum μ 1 ≥ 2 ⋯ with middle eigenvalues H and L where = ⌊( + 1)/2⌋ ⌈( 1)/2⌉, the HOMO–LUMO gap is defined as Δ . In this article, a upper bound for corresponding to special class bipartite graphs estimated. As an application, bounds certain classes nanotubes nanotori are