Four-photon excitation of even-parity Rydberg states in krypton and xenon.

Abstract

Multiphoton ionization via four-photon excitation of high-lying Rydberg states in xenon and krypton has been studied. The p and f series leading to the $^{2}\mathrm{P}_{3/2}$ ionization limits as well as the p' and f' autoionizing levels leading to the $^{2}\mathrm{P}_{1/2}$ limits have been recorded for both gases. Lower members of the p series in xenon are resolved into p${[(5/2)]}_{2}$, p${[(3/2)]}_{2}$, and p${[(1/2)]}_{0}$ sublevels. Ionization potentials and quantum defects are obtained by a least-squares fitting of the data to the standard Rydberg formula.