End-Point Energy Variations in the Noncharacteristic Radiation Produced by S, C1, Ar, K, Ca, and Ti Bombardment of Si

Abstract

The noncharacteristic radiation observed in heavy-ion bombardment of Si was investigated with 200-keV $^{32}\mathrm{S}$, $^{35,37}\mathrm{Cl}$, $^{40}\mathrm{Ar}$, $^{39,41}\mathrm{K}$, $^{40}\mathrm{Ca}$, and $^{48}\mathrm{Ti}$ projectiles ($16<~Z<~22$) on Si. The high-energy tail of the noncharacteristic radiation is observed to shift to higher energies as projectile $Z$ is increased. The observed end-point energy shifts are in agreement with the interpretation that the radiation arises from the radiative decay of a projectile $2p$ vacancy in the quasimolecule formed by the projectile and the target atom during the collision.