Electron Capture At Relativistic Energies

Abstract

This chapter discusses electron capture at relativistic energies. The first investigation of electron capture at relativistic energies was carried out by Mittleman who used a relativistic generalization of the first-order Oppenheimer–Brinkman–Kramer's (OBK) approximation, finding that the asymptotic behavior of the capture cross section was E –1 in the limit of high relativistic energies E . The chapter explains two-state approximation, second-order theories, relativistic continuum distorted wave approximation, and relativistic eikonal approximation. The first quantum-mechanical investigation of electron capture using a second-order theory was carried out by Drisco at nonrelativistic energies. McCann and Deco and Rivarola have developed relativistic theories of electron capture based on spinor continuum distorted waves in the entry and exit channels. Their approach regards the electron as being in a continuum state of the projectile ion in the entry channel and in a continuum state of the target ion in the exit channel. A relativistic generalization of the eikonal approximation has been introduced by Eichler for electron capture.