Populations of np terms in deuterium atoms emergent from carbon foils bombarded with D+, D2+ and D3+ ions

We have measured relative beam-foil populations of 2p, 3p and 4p terms in D0 as a function of the projectile energy (20<=E/M<=500 keV/amu) for D+, D2+, and D3+ ions impinging on carbon foils of various thickness (approx.=2-20 μg/cm2). With D+ projectiles, the np populations reach their equilibirum values even in the thinnest foils used. We compare the dependence on energy of these populations to the equilibirum neutral fraction variation for hydrogen (deuterium) beams emerging from a carbon foil and deduce some information concerning beam-foil populations. When molecular projectiles pass through very thin foils, well known molecular effects appear which depend on the dwell time, t, i.e. the time spent by the projectile in the foil. In this work we consider only the long-dwell-time region t>2 . 10-15s. We study the variation of Rsub(α)=Isup(molec)/Isup(atom)(Isup(molec) and Isup(atom) are the Ly-α intensities per incident deuteron (proton) observed with molecular and atomic projectiles of the same volocity, respectively) with the projectile energy per nucleon (E/M) and the thickness (T) of the foil. For a foil of given thickness, Rsub(α) increases with E/M and reaches a saturation value Rsub(infinite) which decreases when T increases. These results, in agreement with our previous measurements using hydrogen projectiles, indicate that t is not the only parameter relevant to molecular effects. Comparisons are reported between Rsub(α)(E/M) values obtained (a) with H2+ and D2+ projectiles and (b) with D2+ and D3+ projectiles, using foils of various given thicknesses. Ratios Rsub(β)(E/M) and Rsub(γ)(E/M)( are also measured using Ly-β and Ly-γ radiations and compared to Rsub(α)(E/M) values. An interpretation for some of our results is proposed. (orig.)