Atomic and Molecular Physics(DAMP)
Physique atomique et moléculaire (DPAM)

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Peter W. ZETNER
University of Manitoba

Progress in the Investigation of Electron Collisions with Laser Excited Atoms

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The history of electron - atom scattering studies is a long one, dating back to the Franck - Hertz experiment carried out early in the twentieth century. The measurement and calculation of cross sections for various collision processes has been the primary focus of these studies not only because of their intrinsic scientific value but also for their practical utility in the modelling of plasma systems. In the past 25 years, experimental techniques and calculational methods have dramatically improved and new insights into the fundamental physics of the electron - atom collisional interaction have emerged. A particular emphasis has been placed on defining, as completely as possible, the initial and final quantum states of a particular collision process. In this talk, I will discuss atomic target preparation by laser excitation as a means to accomplish this quantum state selection for studies of electron impact excitation / de-excitation, ionization - excitation and elastic scattering. In some instances, laser preparation is sufficient to completely characterize the dynamically relevant quantum numbers. Generally, even when a full characterization is not achieved, the selectivity afforded by laser excitation of an atomic collision target introduces an expanded set of scattering observables which can provide deeper insight into the collision process and furnishes a more demanding test of scattering theories. Some of these "deeper insights" will be presented along with references to recent theoretical improvements motivated by the measurements.