Photoelectron imaging of autoionizing states of xenon: Effect of external electric fields

Abstract

Velocity map photoelectron imaging was used to study the photoelectron angular distributions of autoionizing Stark states of atomic xenon excited just below the Xe + 2 P o 1/2 threshold at fields ranging from 50 to 700 V/cm. Two-color, two-photon resonant, three-photon excitation via the 6p [1/2] 0 level was used to probe the region of interest. The wavelength scans show a similar evolution of structure to that observed in single-photon excitation [Ernst et al., Phys. Rev. A 37, 4172 (1988)]. The photoelectron angular distributions following autoionization of the Stark states provide information on the decay of excited states in electron fields. In the present experiments, the large autoionization width of the ( 2 P o 1/2 )nd[3/2] o 1 series dominates the decay processes, and thus controls the angular distributions. However, the angular distributions of the Stark states also indicate the presence of other decay channels contributing to the decay of these states.

Effect of electronic angular momentum exchange on photoelectron anisotropy following the two-color ionization of krypton atoms

“…A possible explanation for the appearance of these extra rings is that the initially prepared level fluoresces and that the levels populated through this fluorescence are then ionized by a 595 nm photon from the laser beam. Such a mechanism has been observed before in the case of Xe atoms, 30 and is illustrated schematically in Fig. 6.…”