Resonance-enhanced multiphoton-ionization–photoelectron study of the dissociative recombination and associative ionization ofXe2+

Abstract

Two-photon transitions from the ground state of atomic xenon gas, $\mathrm{Xe}{(}^{1}{S}_{0}),$ to ${\mathrm{Xe}}^{\mathrm{*}}$ $\mathrm{nf}$ and $\mathrm{np}$ Rydberg states have been excited in an apparatus that combines ion time-of-flight and photoelectron detection capabilities. Evidence is presented that shows that xenon atoms excited to $\mathrm{nf}$ states with $n=4--8$ undergo rapid associative ionization with ground-state xenon atoms to form ${\mathrm{Xe}}_{2}^{+},$ while those excited to $\mathrm{np}$ states with $n=8--11$ do not. Subsequent ${\mathrm{Xe}}_{2}^{+}$ dissociative recombination (DR) favors exit channels where xenon atoms are formed predominately in $6p$ and $5d$ excited states. Comparisons with older optical studies suggest that photoelectron spectroscopy provides a simple but effective means of studying short-time (ns) DR dynamics.