KINETIC INVESTIGATION OF COLLISION INDUCED EXCITATION TRANSFER IN Kr$^{*}$($4p^{5}$$5p^{1}$) + Kr ($4p^{6}$) AND Kr$^{*}$($4p^{5}$$5p^{1}$) + He ($1s^{2}$) MIXTURES

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Metastable rare gas atoms are gaining increasing interest for their potential in the development of optically pumped laser systems. Understanding the time evolution of excited rare gas states in a collisional environment is of importance for the possibility of exploiting them as the active laser species. Collisional deactivation rates for excited states of Kr$^{*}$($4p^{5}$$5p^{1}$) atoms colliding with ground state Kr ($4p^{6}$) and He ($1s^{2}$) have been measured by time resolved measurements of the laser induced fluorescence, following state selective excitation at room temperature. Collisional energy transfer for the Kr$^{*}$($4p^{5}$$5p^{1}$) + Kr ($4p^{6}$) and Kr$^{*}$($4p^{5}$$5p^{1}$) + He ($1s^{2}$) systems were investigated in a pulsed electrical discharge. Metastable Kr$^{*}$($4p^{5}$$5s^{1}$) was generated by electron impact excitation from the ground state. Using a pulsed tunable dye laser these metastable states were pumped to selected upper levels of the 2$p$$_J$ manifold (Paschen notation) and time-dependent fluorescence decay data from pumped and collisionally populated levels were collected. The total and intramultiplet state-to-state collisional deactivation rate constants were derived from the experimental data and by numerical models. The experimental data were simulated by fitting to numerical solutions of a set of coupled differential equations describing the full collisional relaxation processes. State-to-state rate constants are reported.


Author Institution: Department of Chemistry, Emory University, Atlanta, GA 30322