Photoionization from the5p 2P3/2state of rubidium

Abstract

We report two-step photoionization studies from the 5$p$ ${}^{2}$${P}_{3/2}$ excited state of rubidium using two dye lasers simultaneously pumped by a common Nd:YAG laser in conjunction with a thermionic diode ion detector. The photoionization cross section at the first ionization threshold is measured as 18.8 \ifmmode\pm\else\textpm\fi{} 3 Mb and at excess energies of 0.013, 0.106, 0.229, and 0.329 eV is measured as 15, 13.6, 12.6, and 12.5 Mb, respectively. The measured value of the photoionization cross section at the threshold is used to calibrate the oscillator strengths of the 5$p$ ${}^{2}$${P}_{3/2}$ \ensuremath{\rightarrow} $n$d ${}^{2}$${D}_{5/2}$ (22 \ensuremath{\leqslant} $n$ \ensuremath{\leqslant} 52) Rydberg transitions.