Two-photon spectroscopy of xenon dimers in supersonic jets

Abstract

We report experiments studying the fluorescence and two-photon excitation spectroscopy of xenon dimers and small clusters formed in supersonic jets. Under thermodynamic conditions for maximum dimer density, determined by two-photon resonant multiphoton ionized time-of-flight (TOF) spectroscopy, no fluorescence of free bound excimers correlating to Xe* 6p[1/2]0, 6p[3/2]2, or 6p[5/2]2 was observed; very weak excimer fluorescence was observed for the excimer correlated with Xe+Xe* 5d[1/2]1. Comparing the observed atomic fluorescence and measurements of the monomer-dimer ratio, we estimate predissociation lifetimes on the order of 10-3 of the expected radiative lifetime. TOF spectra are consistent with predissociation for all excimers except those correlating to 6p[5/2]2. At higher nozzle stagnation pressures, we observed fluorescence from vibrationally or electronically relaxed Xe*2 excimers imbedded in helium clusters Hn, with 〈n〉 most probably 6 and 13. We report dispersed spectra, and using modeled reflection spectra, we assign the fluorescence spectra to 6p[1/2]00+g→6s[3/2]1B0 +u, 6p[1/2]00+g→6s[3/2]11 u, and 5d[1/2]10+g →6s[3/2]2A1u. © 1997 American Institute of Physics.