Investigations of Stark effects in xenon Rydberg states by laser-induced fluorescence-dip spectroscopy

Abstract

Stark effects in Rydberg states of xenon atoms were investigated both experimentally and theoretically. The experimental part consisted of laser-induced fluorescence-dip spectroscopy. Using a (2+1)-photon excitation scheme, xenon atoms were excited from the ground state to high-lying Rydberg ns and nd levels. Measurements were made in a controllable electric field environment, produced by applying a pulsed voltage to two parallel metal electrodes. For energy levels with principal quantum numbers ranging from 12 to 18, Stark shifts of up to 4.8 cm{sup -1} were observed for electric fields ranging from 0 to 4000 V/cm. Additionally, mixing of energy levels in high electric fields was measured for nd levels. The experimental results were compared to a theoretical calculation based on solving the Schroedinger equation for a perturbed Hamiltonian. The calculation method proved to be very accurate for predicting Stark effects in Rydberg nd levels, while for ns levels the agreement was only moderate, probably due to deviations from the assumption of a hydrogenlike atom that is used in the calculation. Finally, the feasibility of using measurements of Stark shifts of Rydberg levels as a diagnostic for electric fields in low-pressure discharges was discussed.