High l state population in O7+ produced in ion-solid collisions

The high ell-state population of fast ions excited in ion-solid interactions is very different from ell-state populations produced under single collision conditions. A study of the population dynamics of electronic excitation and transport within the framework of a classical transport theory for O2+ (2 MeV/u) ions traversing carbon foils shows food agreement with experimental results from delayed photon emission spectroscopy. We investigate the dependence of the characteristic exponent for the power-law decay of delayed Lyα and Lyβ radiation on the initial n,ell distribution. From our simulations we find evidence that the very high ell-state populations produced in ion-solid collision are the consequence of a high-ell state diffusion under the influence of multiple inelastic and elastic collisions in the bulk of the solid. 15 refs., 4 figs