Photoionization and Collisional Ionization of Excited Atoms using Synchrotron and Laser Radiations

Abstract

Publisher Summary This chapter presents various ionization processes such as photoionization, autoionization, and collisional ionization to be examined in excited atoms. The photon energy range from threshold to several hundred electron volts above threshold provides the most fruitful region to study these many body interactions. The information obtained from these measurements, while having great value, is somewhat restrictive because of the dipole selection rules. Only a limited class of states can be probed and the initial state is often an ensemble of nearly degenerate levels. Synchrotron radiation is a source of radiation that extends over a spectral range extending from x-rays to microwaves. Because of its intensity, synchrotron radiation is ideally suited for the observation of photoionization in gaseous samples. Most of the electrostatic interaction occurs within the core and the d wave function amplitude increases slowly with increasing radial distance. The overlap of the wave function of the excited d electron with the core is small in neon, but much larger for these other rare gases.