ELASTIC, POSITRONIUM FORMATION AND 2P-EXCITATION CROSS-SECTIONS OF E(-LI SCATTERING())

Inelastic-collision processes, in which elastic, positronium formation and Bp-excitation channels ape open, have been investigated for the f irst time within the framework of the coupled-static and frozen-core a pproximations. Rayleigh-Ritz variational method has been employed for calculating the binding energies and wave functions of the Is, 2s and 2p states of the lithium atom. The partial cross-sections correspondin g to 7 values of the total angular momentum I (0 less than or equal to l less than or equal to 6) are determined for 9 values of the inciden t energy lying between 1.8 and 10 eV. Our results illustrate the stabi lity of the iterative numerical technique employed. They demonstrate t he role played by each partial wave in the total cross-sections and th e importance of considering the positronium formation channel in all i nelastic collisions of positrons by the atoms of alkali metals in the low-energy region. They also show that the Bp-excitation channel is ve ry important in the same energy range.