Electron Shake-Up in Two-Photon Excitation of Core Electrons to Rydberg Autoionizing States

The results of a theoretical and experimental investigation of satellite line strengths in two-photon transitions to Rydberg autoionizing states in multielectron atoms are presented. In studies of $6snd-7s{n}^{\prime }d$ two-photon transitions in Ba I, the distribution of line strengths over various final $7s{n}^{\prime }d$ states for a given $6snd$ initial state is found to vary dramatically as a function of detuning from intermediate $6p{n}^{\prime \prime }d$ autoionizing resonances. These results indicate the influence of electron rearrangement during the multiphoton transition.