Dynamics ofHe2++H(1s)ionization with screened Coulomb interactions

Abstract

Collision dynamics of ${\mathrm{He}}^{2+}+\mathrm{H}(1s)$ ionization in a hot, dense (Debye) plasma is studied by the two-center atomic orbital close-coupling (AOCC) method in the energy range $5--300\phantom{\rule{0.3em}{0ex}}\mathrm{keV}∕\mathrm{u}$. The target AO basis contained all $n\ensuremath{\le}6$ bound states and 117 quasicontinuum states, while that on the projectile contained all $n\ensuremath{\le}4$ bound states. The eigenenergies and wave functions of all these states were obtained variationally as a function of the screening parameter in a Debye-H\"uckel potential and used in AOCC dynamics calculations. With increasing the screening, more and more discrete states enter the target and projectile continuum and increase the ionization cross section, particularly at low collision energies. The ionization to target continuum is the main ionization channel, while the ionization to the projectile continuum becomes important only for large screenings and collision energies below $\ensuremath{\sim}50\phantom{\rule{0.3em}{0ex}}\mathrm{keV}∕\mathrm{u}$.