Population of He 4¹D magnetic sublevels by collisions with protons and multiply charged ions in the intermediate velocity range

Abstract

The authors have investigated the collisional excitation of He by protons and multiply charged ions at intermediate velocities applying the optical method. The population of the magnetic sublevels of He 41D has been determined using level-crossing techniques for a variety of projectiles with charges ranging from 1+ to 23+ and velocities between 1 au and 7 au. The relative excitation cross sections sigma M/ sigma 41D of the Zeeman substates turn out to be universal functions UM( nu 2/q) of the projectile velocity nu and charge q. Total excitation cross sections of the 31P, 41S and the 41D state are included for a discussion of the scaling relation sigma /q=f( nu 2/q).

Electron- and proton-impact excitation of heliumlike uranium in relativistic collisions

“…Heavy-ion storage rings, such as the Experimental Storage Ring (ESR) at GSI in Darmstadt, equipped with internal gas targets have provided very favorable conditions to extend the former studies of the excitation process for low-and mid-Z ions ( [7][8][9][10][11][12][13][14][15]) into the high-Z regime. Namely, the excitation of projectile electrons due to the interaction with the target nucleus (PIE) has been addressed in detail for very heavy hydrogen-and heliumlike ions (see, e.g., Refs.…”

Ground-state excitation of heavy highly-charged ions

“…The excitation processes have been intensively studied for light [23][24][25] to medium heavy ions [26][27][28][29][30][31], whereas in the high-Z regime the experimental investigations have been relatively scarce. This situation has changed since the advent of dedicated heavy ions accelerators and storage rings such as the experimental storage ring (ESR) at GSI Darmstadt.…”

Coulomb excitation of helium atoms in collisions with highly charged ions

“…Regarding the total excitation cross sections, this JP scaling law has been verified experimentally by Reymann et al [7], disregarding some minor deviations found for proton impact (q = 1). The JP scaling law was also found to be valid with respect to the relative population rates of Zeeman sublevels [8,9].…”