Laser photodetachment electron spectroscopy studies of heavy atomic anions

Laser photodetachment electron spectroscopy (LPES) experiments have been performed at the Negative Ion Research Facility at the University of Nevada, Reno, using a crossed ion-laser beams apparatus to investigate the structure and dynamics of heavy atomic anions. A small ion accelerator is used to produce monoenergetic beams of negatively-charged atomic ions. Ejected electrons (photoelectrons), produced by the collision of the ions with linearly-polarized photons, are collected and their kinetic energy is measured with a hemispherical-sector electrostatic analyzer. The resultant photoelectron spectrum is used to determine the electron affinity (EA) of several of the lanthanides, while limits on the electron affinities for others are inferred. In addition, the angular asymmetry parameters and angular distribution patterns of photoelectrons created by laser photodetachment of several heavy atomic anions, as well as the spectral dependence of those angular distributions, have been determined. Electron affinities and photoelectron angular distribution asymmetry parameters can offer crucial information regarding the electronic structures of these heavy atomic anions, and represent key information for models of these complex systems. (c) 2005 Elsevier B.V. All rights reserved.