Radiative lifetimes, absorption cross sections, and the observation of new high-lying odd levels of ^238U using multistep laser photoionization*

Abstract

We report the observation of over 100 new high-lying odd levels in atomic uranium between 32 600 and 34 200 cm⁻¹ using tunable laser techniques. These augment the 32 odd levels previously determined in this energy regime by conventional atomic spectroscopy. The method used in these studies, multistep photoionization under pulsed dye laser excitation, was also employed to make J assignments, measure radiative lifetimes, and to obtain absorption cross sections of transitions involving these levels.