The time dependence of the optogalvanic signals induced by 1sjrarr;2pk(Paschen notation) pulsed laser excitations of neon in a low power sim;30 MHz radio frequency (rf) discharge at sim;5 Torr has been investigated. The method of Kumar and McGlynn lsqb;Chem. Phys. Lett.176, 536 (1991)rsqb; has been improved and is used to separate the temporal profiles of the optogalvanic signals into two components: one attributable to ionization rate changes and the other to acoustic effects. This separation simplifies the identification of the kinetic processes which produce optogalvanic signals. Selective laser excitation of 2pkstates, ones which possess quite different decay branching ratios to the metastable and nonmetastable 1sjstates, reveals time dependencies due to unique perturbations of specific 1sjpopulations. No dimer mediated nor, indeed, any effects associable with 2pkstate populations contribute to the profiles. Competitive processes which increase or decrease the ionization rates are identified attge;1 mgr;s. The extensive broadening of the acoustic and ionization components is caused by radiation trapping of 1s2rarr;1S0and 1s4rarr;1S0photons.
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