Energy Transfer in Multi-Ionizing Ion/Cluster Collisions

Abstract

Sodium clusters Nan in the size range 20 < n < 600 have been ionized in single collisions with multiply charged ions at velocities between 0.4 and 0.9 a.u.. Depending on the initial charge state z of the projectile (1 < z < 28), stable cluster ions are produced in charge states r ranging from 1 to ∼ 11. As the stability of multiply charged clusters depends on their internal energy, we have analyzed the appearance sizes in order to determine the cluster temperature and hence the energy which has been transferred to the target during the ionizing collision. This energy depends on whether penetrating collisions are required to create a given charge state or not. In the case of highly charged projectiles (distant collisions) the transferred energy can be as low as 1–2 eV for five-fold ionization