Calculation of the E.S.R. spectrum shape of the dynamic biradical system

Abstract
The E.S.R. spectrum shape of a dynamic biradical system is calculated by means of the density spin-matrix formalism. The biradical is treated as a system which has two conformations characterized by the different values of the exchange integrals J=J 1 and J=J 2 and the lifetimes τ1 and τ2 respectively. The influence of both the rate and the strength of exchange interactions on the shape of the spectrum is discussed. Criteria to distinguish the spectra of the cases of both slow and fast exchange are discussed.