Abstract

Introduction. In the theory of electron capture the exchange interactions at large internuclear distances R between projectile and target particles are the most important ones, since they are associated with the largest cross sections. However, their accurate calculation in the asymptotic region of large R by standard ab initio techniques still requires significant computational effort. In the case of two-electron exchange interaction the situation is much complicated due to necessity of the usage of analytic approximation for the two-electron wave function which must have correct asymptotic (at large R) behavior in whole configuration space of the electronic coordinates. This requirements can be satisfied by using the method of surface integrals and the Green’s function formalism. The present studies devoted to construction of asymptotically correct two-electronic wave function and two-electronic exchange interaction of the system which consist of the atomic ion and polar molecule.
Purpose. To construct a closed analytical expression for two-electron exchange interaction potential, which defines the charge-exchange processes between the polar molecule and multicharged ion.
Results. Within the framework of a semiclassical approach and approximation of a coulomb-dipole potential the closed analytical expression of the two-electron exchange interaction responsible for two-step mechanism of charge-exchange between the polar molecule and multicharged ion has been obtained.
Conclusion. We have constructed the semiclassical representation for two-electron wave function of the quasimolecular system which consist of polar molecule and atomic ion for large separation R between heavy particles. Using obtained results a closed analytical form (in terms of full elliptic integrals) of the leading asymptotic term of exponentially small two-electron exchange interaction between the polar molecule and atomic ion has been obtained. The derived expression for exchange interaction can be used for study of the two-electron transfer processes in collision of polar molecules with atomic ions

Keywords: polar molecules, slow ion-molecular collisions, two electron exchange interaction, asymptotic theory

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