Projectile dependence of single-excitation cross sections at intermediate velocities.

Abstract

We study 1s\ensuremath{\rightarrow}2s(2p) excitation of hydrogen as a function of the nuclear charge of the projectile, ${\mathit{Z}}_{\mathit{P}}$, for a fixed impact velocity, v=1.3 a.u., for which electron excitation, capture, and ionization are competitive processes. For this purpose, we have performed large ab initio close-coupling calculations using a molecular basis in the framework of the impact-parameter method. Excitation probabilities do not saturate when ${\mathit{Z}}_{\mathit{P}}$ increases indefinitely, in agreement with recent work of Janev and with theoretical evidence on the behavior of transition probabilities at high impact energies. \textcopyright{} 1996 The American Physical Society.