Dissociative recombination in xenon: Variation of the total rate coefficient and excited-state production with electron temperature

A three-mode microwave afterglow apparatus has been used in conjunction with a high-speed grating spectrometer to study the variation with electron temperature of the recombination coefficient α (Xe2+) and of the Xe* excited states produced by dissociative recombination over the range 300 < or = T/sub e/ < or = 8000 K. At low electron temperatures, 300--700 K, α (Xe2+) varies approximately as T/sub e/-1/3, with a smooth transition to a approx.T/sub e/-0/sup ./7 variation at higher electron temperatures, 1300--7400 K. At T/sub e/ = T/sub +/ = T/sub n/ = 300 K, α (Xe2+) = (2.3 +- 0.2) x 10-6 cm3/sec, in agreement with earlier studies at room temperature. At thermal energy (300 K) Xe* excited states up to but not exceeding the energy of the Xe2+ ion in its ground electronic and vibrational state are observed. With microwave heating to T/sub e/ approx. 8000 K additional, higher-lying Xe* states (up to approx.0.6 eV above the Xe2+ ion ground state) are produced by the dissociative recombination process