Electron transfer and ionization in collisions between protons and the ions He+, Li2+, Be3+, B4+, and C5+ studied with the use of a Sturmian basis.

Abstract

Total cross sections are reported for electron transfer and ionization in collisions between protons and the hydrogenic ions ${\mathrm{Be}}^{3+}$, ${\mathrm{B}}^{4+}$, and ${\mathrm{C}}^{5+}$, and results are presented for ${\mathrm{He}}^{+}$ and ${\mathrm{Li}}^{2+}$ in addition to those previously reported. Proton energies relative to the target ion are in the range 17.5--150 keV for ${\mathrm{He}}^{+}$ targets, increasing with the target's nuclear charge to 150--600 keV for ${\mathrm{C}}^{5+}$ targets. Within these energy ranges the electron-transfer cross sections reach their peak values, and the ionization cross sections approach peak values from below. A coupled-Sturmian-pseudostate approach has been taken, and the largest-basis results are estimated to be converged to within 10% at energies where the electron-transfer cross sections peak. With sufficiently large bases, the cross-section curves vary smoothly and regularly with energy and the target's nuclear charge. Scaling rules for these curves are examined and compared with the simple scaling laws in the Born approximations.