Relating Estrada index with spectral radius

• Main Authors: Gutman Ivan, Radenković Slavko, Furtula Boris, Mansour Toufik, Schork Matthias
• Format: Article
• Language: English
• Published: Serbian Chemical Society 2007-01-01
• Series: Journal of the Serbian Chemical Society
• Subjects: molecular graph; estrada index; spectral radius; graph spectrum
• Online Access: http://www.doiserbia.nb.rs/img/doi/0352-5139/2007/0352-51390712321G.pdf

The Estrada index EE is a recently proposed molecular structure-descriptor, used in the modeling of certain features of the 3D structure of organic molecules, in particular of the degree of folding of proteins and other long-chain biopolymers. The Estrada index is computed from the spectrum of the molecular graph. Therefore, finding its relation with the spectral radius r (= the greatest graph eigenvalue) is of interest, especially because the structure-dependency of r is relatively well understood. In this work, the basic characteristics of the relation between EE and r, which turned out to be much more complicated than initially anticipated, was determined.