Radiative lifetimes and collisional deactivation of two-photon excited xenon in argon and xenon

Abstract

Radiative lifetimes and bimolecular rates have been determined for two-photon laser excited states of Xe* (5p56p, 5p56p′, 5p57p) in argon and xenon buffer gases. The collisional deactivation rates are found to be very large for the Xe 6p′ and 7p states [∼(2–5)×10−10 cm3/s] while the rates for the Xe 6p states are comparatively smaller [∼(0.06–1.2)×10−10 cm3/s]. In general, the quenching rates in argon are about a factor of 2 smaller than the xenon quenching rates for the same excited state with the notable exception of Xe 6p[1/2]0. For Xe 6p[1/2]0, a multicomponent decay has been observed in argon buffer gases. The second component is attributed to collisional coupling to Xe 5d[1/2]1 which lies 132.3 cm−1 below Xe 6p[1/2]0. Quench rates determined from the collisionally induced VUV fluorescence from Xe 5d[1/2]1 at 125 nm are in excellent agreement with this assignment. Furthermore, these experiments have unambiguously identified the product channel involved in the curve crossings observed in studies of optical collisions [N. Böwering, T. D. Raymond, and J. W. Keto, Phys. Rev. Lett. 52, 1880 (1984)].