Electron scattering from hydrogen atom in dense semi-classical hydrogen plasma: S-wave resonance states

The existence and the behaviour of the resonance states in the scattering of electrons from the hydrogen atoms under semi-classical plasma environments are investigated. The organized effect of the plasma charged particles is modelled by a pseudopotential which takes care of the quantum mechanical effect of diffraction at short distances as well as the collective effect of the plasma particles by means of two adjustable parameters, namely the de Broglie wavelength lambda and the screening parameter K . An extensive square-integrable basis set is employed within the framework of the stabilization method to determine the S-wave resonance states in the e-H system. In particular, the emergence of three S-wave singlet resonance states is identified by noting the stabilized energy levels, whereas the energy and the width of those states are computed from the fitting of the density of the states with the Lorentzian form. The results for the plasma-free case are in good agreement with the established results in the literature. A comprehensive study is made on the changes in the energy and width of the resonance states as a result of variation in lambda at a given K