Dynamics ofHe2++H(1s)excitation and electron-capture processes in Debye plasmas

Abstract

Collision dynamics of the ${\mathrm{He}}^{2+}+\mathrm{H}(1s)$ system imbedded in a 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 atomic orbitals and electron binding energies of atomic states are calculated within Debye-H\"uckel approximation of the screened Coulomb potential and used in AOCC dynamics formalism to calculate the state-selective electron capture and excitation cross sections. The basis contained 174 orbitals centered on the target (all $n\ensuremath{\le}6$ discrete states and 117 quasicontinuum states) and 20 orbitals centered on the projectile (all $n\ensuremath{\le}4$ discrete states). It is demonstrated that the screening of Coulomb interactions in the system progressively reduces the number of available excitation and electron capture channels when the screening parameter increases. The screening of Coulomb interactions introduces changes also in the values of direct and exchange couplings, thus affecting the magnitude and energy behavior of the cross sections. The control of dynamics of collision processes in a Debye plasma by varying the plasma screening of Coulomb interactions in the collision system is discussed.