The Minimum Estrada Index of Spiro Compounds with k Quadrangles

Document Type: Research Paper

Authors

Yazd University

10.22052/ijmc.2019.149094.1392

Abstract

Abstract. Let G = (V,E) be a fi nite and simple graph with λ1, λ2,...,λn as its eigenvalues.The Estrada index of G is EE(G) =∑ni=1e^{λi} . A spiro compound is a chemical compound that presents a twisted structure of two or more rings, in which 2 or 3 rings are linked together by one common atom. In this paper, we show that the symmetric and stable spiro compounds among all spiro compounds have the minimum Estrada index.

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