Excitation of atomic hydrogen by fully stripped ions

Excitation of atomic hydrogen in initial quantum levels ${\mathit{n}}_{\mathit{i}}$=1,2,3 colliding with multiply charged ions with charge states q from 1 to 26 is investigated in the impact energy range 10 (keV/u)/${\mathit{n}}_{\mathit{i}}^2$–10 MeV/u, by means of the classical trajectory Monte Carlo, many-state atomic orbital close-coupling, and symmetric eikonal formalisms. This extensive compilation of theoretical calculations confirms the feasibility of an empirical scaling relation (σ/q vs E/q) proposed in previous works to reduce the excitation cross sections induced by multiply charged ions to a single universal curve. This scaling, together with the semiempirical formula derived by Lodge and co-workers [J. Phys. B 9, 239 (1976)] for proton projectiles, is found to provide reliable excitation cross sections for the one-electron collision system. Good agreement is obtained between theory and experiment for proton impact on H(1s) at impact energies above 10 keV.