Energy of some cluster graphs

The energy of a graph G is defined as the sum of the absolute values of the eigenvalues of G. The graphs with large number of edges are referred as graph representation of inorganic clusters, so-called cluster graphs. I. Gutman and L. Pavlovic introduced four classes of graphs obtained from complete graph by deleting edges and obtained their spectra and energies. In this paper we introduce another class of graph obtained from complete graph by deleting edges and find its energy. Some results of I. Gutman and L. Pavlovic, become particular cases of our results.