Momentum-space coupled-channels optical method for electron-atom scattering

A complete account is given of a new method for the solution of the problem of electron scattering by a one-electron atom or ion. The method treats all relevant effects explicitly. Reaction channels under consideration are treated by the coupled-channels method in momentum space. Other channels, including the continuum, are treated by adding complex-polarization potentials computed from experimentally tested approximate amplitudes for the relevant reactions. Computational methods are discussed in detail since this is the first successful application of the momentum-space solution to the atomic multichannel problem. The effect of the inclusion of channels outside the coupled space is demonstrated by comparison with three-state close coupling for hydrogen at 54.42 eV.