arXiv subjects

H R J Walters

Publications and source records attributed to H R J Walters.

2 recordsLinked to original sources

arXiv2004

Positronium-Atom Collisions

New results are presented for Ps(1s) scattering by H(1s), He(1$^1$S) and Li(2s). Calculations have been performed in a coupled state framework, usually employing pseudostates, and allowing for excitation of both the Ps and the atom. In the Ps(1s)-H(1s) calculations the H$^-$ formation channel has also been included using a highly accurate H$^-$ wave function. Resonances resulting from unstable states in which the positron orbits H$^-$ have been calculated and analysed. The new Ps(1s)-He(1$^1$S) calculations still fail to resolve existing discrepancies between theory and experiment at very low energies. The possible importance of the Ps$^-$ formation channel in all three collision systems is discussed.

physics.atom-ph↗

arXiv2004

Ionization of hydrogen and ionized helium by slow antiprotons

We study the ionization process involving antiproton and hydrogen in the energy range between 0.1 keV to 500 keV, using single center close coupling approximation. We construct the scattering wave function using B-spline bases. The results obtained for ionization of atomic hydrogen are compared with other existing theoretical calculations as well as with the available experimental data. The present results are found to be encouraging. We also employed this method to study the ionization of ionized helium in the energy range between 1 and 500 keV. On comparision, the present results are found to interpret well the cross section values calculated using other theories.

physics.atom-ph↗