QUENCHING RATE CONSTANTS OF THE XE(5P(5)6P AND 6P') STATES AND THE ENERGY-POOLING IONIZATION REACTION OF XE(5P(5)6S) ATOMS

Two-photon excitation by a pulsed dye laser was used to prepare the Xe(5p(5)6p[1/2](0), [3/2](2), [5/2](2)) and Xe(5p(5)6p'[1/2](0), [3/2](2)) states in the presence of several reagent gases to measure total quenching rate constants at 300 K. The new measurements together with rate constants from the literature provide a general overview of Xe(6p) atom reactivity, especially with halogen- and oxygen-containing molecules. Reactive quenching and/or excitation transfer to the reagent molecule are the dominant quenching mechanisms, rather than intramultiplet transfer to other states of the Xe(6p) manifold. The XeCl(B and D) and XeF(B and D) product state distributions from reactions of the Xe(5p(5)(P-2(1/2))6p') states with HCl, Cl-2, F-2, NF3, CCl4, and CCl2F2 were observed in order to record the degree of conservation of the Xe+(P-2(1/2)) core as indicated by XeCl(D) or XeF(D) formation. Except for the HCl reaction, the Xe+(P-2(1/2)) core does not have a high degree of conservation in reactions of Xe(6p') atoms. For conditions of low reagent pressure, radiative decay of the Xe(6p) states can produce a high local concentration of metastable Xe(6s) atoms, which subsequently undergo bimolecular, energy-pooling, associative-ionization reactions. The Xe-2(+) ions subsequently recombine with electrons to generate a variety of excited Xe* states.