بعضی مراتب پایینی جدید برای انرژی گراف

The energy of a graph G, denoted by E(G), is defined as the sum of the absolute values of all eigenvalues of G. In this paper we present some new lower bounds for energy of non-singular graphs, connected non-singular graphs and connected unicyclic non-singular graphs in terms of number of vertices, number of edges, maximum degree and Zagreb indices.