QUENCHING RATE CONSTANTS AND PRODUCT ASSIGNMENTS FOR REACTIONS OF XE(7P[3 2](2), 7P[5/2](2), AND 6P'[3/2](2)) ATOMS WITH RARE-GASES, CO,H-2,N2O,CH4, AND HALOGEN-CONTAINING MOLECULES/

Two-photon excitation of Xe atoms in a static gas cell was used to pre pare the Xe(7p[3/2](2), 7p[5/2](2), and 6p'[3/2](2)) states in mixture s of Xe with rare gases, H-2(D-2), CO, Cl-2, HCl, CCl2F2, CCl4, SF6, N S, CF4,CH4, CH3F, and N2O at 300 K. The total quenching rate constants were measured, and product fluorescence spectra were used to assign r eaction pathways. The total quenching constants for these Xe Rydberg states by molecular reagents are very large, corresponding to cross se ctions of 200-1500 Angstrom(2). Qualitative models are introduced to d iscuss the quenching processes, which are mainly reactive quenching an d excitation transfer. For reagents with very large electron affinitie s, ion-pair formation may be important. A correlation of the quenching cross section with the dipole moment of the reagent was observed. The se three Xe states have nearly the same energy (similar to 11 eV), bu t the Xe(7p) states nominally have the Xe+(P-2(3/2)) ion-core, whereas the Xe(6p') states have the Xe+(P-2(1/2)) core. The XeCl(D) and XeF(D ) states also have the Xe+(2P(1/2)) core, and the fraction of XeCl(D) and XeF(D), relative to XeCl(B,C) or XeF(B,C), formed by the reactions of Xe(6p'[3/2]2) atoms with halogen-containing reagents can be used t o measure the degree of conservation of the Xe+(P-2(1/2)) core. The Xe (7p) and Xe(6p') reactions actually gave nearly the same B and D distr ibutions, with XeCl(B) and XeF(B) being favored, and the Xe+(P-2(1/2)) ion-core state is not conserved during the reactions of Xe(6p') atoms . Two-photon excitation of the Xe(7p,6p') states leads to intense ampl ified spontaneous emission (ASE) unless special feature are incorporat ed into the experimental design. This ASE emission can cause complicat ions because other Xe states are generated during the laser pulse. Th e measurements reported here are free from ASE, but some consequences of ASE for experiments with Xe(6p' and 7p) excitation are summarized. The relative two-photon cross sections of the Xe(6p, 6p', 7p) states a lso are discussed.