Positron-lithium atom and electron-lithium atom scattering systems at intermediate and high energies

The coupled-channel optical method is used to study positron scattering by atomic lithium at energies ranging from the ionization threshold to 60 eV. The present method simultaneously treats the target channels and the positronium (Ps) channels in the coupled-channel method together with the continuum effects via an ab-initio optical potential. Ionization, elastic and inelastic cross sections in target channels, and the total cross section are also reported and compared with other theoretical and experimental data. A comparative study with the corresponding electron-lithium data is also reported.