Excitation of Be⁺and Mg⁺in collisions with rare gases: measurements of Be II and Mg II resonance line emission and polarization

Emission cross sections and polarizations have been measured for the 2 2 S-2 2 P Be II multiplet in collisions between 0.3-70 keV Be + ions and He or Ne, and the 3 2 S-3 2 P, 3 2 P-3 2 D and 3 2 P-4 2 S Mg II multiplet components in collisions between 1-150 keV Mg + ions and the rare gases. The excitation of the projectile resonance multiplet is found to be the dominating inelastic process for all collision systems. The ratio between the cross sections for the fine-structure components in magnesium is constant and equal to the statistical weight ratio 2:1. Cascade effects are shown to be important at higher energies. The results are compared with related experiments by Kempter et al. (1974) and Ovchinnikov et al. (1974). Some characteristic features are in agreement with the predictions of the one-electron model calculations of Nielsen and Dahler (1976).