Xenon microdischarge at 300-800 torr: laser spectroscopy of Xe2 a3Σu+(1u,0u-)

Spatially uniform microdischarges in Xe at pressures of 300-800 torr have been produced in a 90-μm gap between 1.5-mm-diameter tungsten rods (plasma volume of ∼160 μL), and applied to the laser spectroscopy of the Xe₂ excimer. Calculations and spectral simulations indicate that the gas temperature in the plasma reaches 900 K for a steady-state current density of 0.23 A-cm^-2. Laser-induced, fluorescence suppression spectroscopy in the afterglow of the crow-barred discharge reveals well-developed vibrational bands in the 680-800-nm region tentatively attributed to 5(1_g)←a³Σ_u⁺(1_u,0_u^-) transitions of Xe₂.