Many-body theory of the generalized optical potential for electron-atom (molecule) inelastic scattering

Abstract

Using the Martin-Schwinger variational technique (1959), a new theory is obtained for electron-atom (molecule) inelastic scattering. This theory constitutes a higher order approximation than the GRPA elastic theory. In analogy with elastic scattering, an equivalent optical potential, named, the transition potential, is introduced for inelastic scattering. In the GRPA this transition potential is of the first-order static-exchange type. The present theory adds three new effects to the GRPA transition potential. One of them represents the screening of the first-order exchange term, another one the transition polarization effect and the third the effect of the final state field. In contrast to close-coupled or Kohn-type variational theories, the present theory has the advantage of decoupling the scattering channels through the use of the energy-dependent transition potential.