Optical Spectroscopy of Highly Ionized Neon

The recent development of sources such as the recoil ion source fl], producing highly charged, low energy (HQLE) ions presents the possibility of bringing highresolution Iascr spectroscopy to the study of highty tharged ions. A prerequisite For performing these measurements is the preparation of the HQLE ions quantum states which participate in transitions accessible to tunable lasers. For this purpose, one can exploit electron transfer collisions which selectively populate highly excited states of slow ions. Optical studies on these ions would also permit a thorough understanding of the electron capture process itself. Knowledge of the partial cross sections for capture into the various (n, I, nr) substates of the projectile ion plays an important role in these endeavors. Theories of varying complexity exist for predicting these distributions. The well-known classical barrier model {CB_M) is a simple yet useful model for describing electron transfer f2]. It allows a prediction of the principal (tz) quantum number characterizing the states most likely to be populated in collisions involving slow, highly ionized species. More intricate theories are necessary for predicting the distribution of angular momentum (I) and magnetic (m) substates populated by electron transfer. Such distributions have been obtained for collision systetns consisting of bare projectile ions and Ii (1s) atoms f3]. Calculation of the 1, m distributions demands that one take proper account of the Stark mixing of projectile ion substates in the electric field of the residual target ion. When projectile ions with core electrons are used, the i substates into which electrons are captured become nondegenerate. One must therefore reconsider