High-resolution photoelectron spectrometric analysis of the decay of the 4pexcitations in atomic strontium

In a high-resolution analysis of the electron spectrum we have followed the decay of the excitations from the 4p level of atomic strontium. We show that the results of earlier measurements at lower resolution can be accounted for by overlapping resonances. We also find that excitations at higher energy tend to produce highly excited states of the ion, although the production of the states lying lowest in energy remains considerable. Finally, by a comparison with a fluorescence spectrum from the 5p level, we demonstrate that much of the strength associated with the 5p state occurs through cascading from higher levels when they are produced. This behavior severely complicates the interpretation of alignment of excited states when these states are produced by decay of resonances.