Alkanes with Greatest Estrada Index

Abstract

If λ1 > λ2 ≥ λ3 ≥ · · · ≥ λn are the eigenvalues of the molecular graph, then the Estrada index, a recently conceived molecular structure-descriptor is \(EE = \sum_{i=1}^{n} e^{\lambda_i}\). The same alkanes, whose molecular graphs have extremal Wiener indices and λ1, are shown to be also extremal with regard to the Estrada index.