Resonances in Photoelectron Angular Distributions

Abstract

Photoelectron angular distributions should show pronounced variations with energy across autoionization resonances. This prediction applies quite generally to both atomic and molecular autoionization. Examples illustrate both the magnitude of the spectral variation and the inability of the Cooper-Zare model to account for the phenomenon. Calculations are reported for autoionization in xenon between the fine-structure levels $5{p}^{5} ^{2}P_{\frac{3}{2}}^{\ensuremath{\circ}}$ and $5{p}^{5} ^{2}P_{\frac{1}{2}}^{\ensuremath{\circ}}$ of the ion ground-state doublet. An analysis is given of the recent measurements by Niehaus and Ruf on autoionizing levels of the mercury Rydberg series $5{d}^{9}6{s}^{2}(^{2}D)np$ and $5{d}^{9}6{s}^{2}(^{2}D){n}^{\ensuremath{'}}f$ below the ${\mathrm{Hg}}^{+}$ $5{d}^{9}6{s}^{2} ^{2}D_{\frac{5}{2}}$ threshold.