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 Xe2(*) excimers imbedded in helium clusters H-n, with [n] most probably 6 and 13. We report dispersed spectra, and using modelled reflection spectra, we assign the fluorescence spectra to 6p[1/2](0)0(g)(+) --> 6s[3/2](1)B0(u)(+), 6p[1/2](0)0(g)(+) --> 6s[3/2](1)1(u), and 5d[1/2](1)0(g)(+) --> 6s[3/2](2)A1(u). (C) 1997 American Institute of Physics.