ABSTRACT
Photoelectron angular distributions should show the pronounced variations with energy across autoionization resonances. This prediction applies quite generally to both atomic and molecular autoionization. That photoelectron angular distributions should vary markedly with energy across a resonance in the integrated cross section follows from the analytical structure of the asymmetry parameter. Therefore, the measurement of resonances in the photoelectron angular distributions should yield results that can deviate considerably from those predicted by the Cooper-Zare model. A fundamental concept of the multichannel quantum-defect theory is the resolution of the ionization process into an initial photon absorption and the photoelectron’s subsequent interaction with, and escape from, the target. These two aspects of the process contribute different characteristic elements to the ionization dynamics. Resonant structure in the photoelectron angular distributions is predicted to be a general feature of all atomic and molecular autoionization resonances.
