title: Observation of the phase lag in the asymmetric photoelectron angular distributions of atomic barium.
abstract: We have observed and measured the phase lag in the phase-dependent variation of the asymmetric photoelectron angular distribution of atomic barium. For these measurements, we photoionize the 6s6p(1)P(1) intermediate state of barium with concurrent one-photon and two-photon (omega-2omega) interactions. The laser interactions ionize the atoms in the vicinity of the series of autoionizing states converging upon the 5d(2)D(5/2) threshold. We study the variation of the phase lag as a function of the laser frequency. The variation shows strong correlation to the location of the autoionizing resonances, with full range exceeding 2pi, confirming the critical role of these resonances.
authors.affiliation: School of Electrical and Computer Engineering and Department of Physics, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Rekishu
authors.initials: R
authors.lastname: Yamazaki
authors.forename: D S
authors.initials: DS
authors.lastname: Elliott