Schwinger variational calculations for electron scattering by polar molecules

The authors present the results of applications of the Schwinger variational principle to the scattering of low-energy electrons by the strongly polar molecule LiH. The method is based on an iterative approach which uses the Schwinger variational principle to solve the Lippmann-Schwinger integral equation for the scattering wavefunction. The procedure uses trial scattering wavefunctions which contain both discrete basis functions and numerical continuum wavefunctions which satisfy explicitly the scattering boundary conditions. The results of these applications show that the method is an effective approach to the solution of the electron-molecule scattering equations. Several details of the method are discussed.