Photoionization cross section of lead near the 6s26p 2P3/2 threshold.

Abstract

Measurements of the total photoionization cross section of lead in the energy range between the 6${\mathit{s}}^{2}$6p${(}^{2}$${\mathit{P}}_{1/2}$) ionization threshold at 59 819 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ and the 6${\mathit{s}}^{2}$6p${(}^{2}$${\mathit{P}}_{3/2}$) threshold at 73 900 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ are reported. Just above the ionization threshold the cross section is dominated by broad window resonances, members of the 6pnd and 6pns Rydberg series converging to the 6${\mathit{s}}^{2}$6p${(}^{2}$${\mathit{P}}_{3/2}$) threshold. The Rydberg series are perturbed by a very broad and intense autoionizing resonance near the threshold. The resonance energy, width, and shape parameter of this resonance are determined. Close to the 6${\mathit{s}}^{2}$6p${(}^{2}$${\mathit{P}}_{3/2}$) series limit the data indicate the presence of a further broad-window-type resonance.