Decay of Krypton1s2and1s3Excited Species in the Late Afterglow

Experimental investigations of the behavior of the Kr $1s_2$ excited-state population in after-glow discharge plasmas are described. The number density of Kr $1s_2$ atoms was obtained by performing resonant absorption measurements at 8509 Å $(\mathrm{Kr} 1s_2\to 2p_4)$ with a tunable GaAs laser diode. The narrow-width laser was tuned and swept through the entire resonant transition. The decay of the $1s_2$ species in the late afterglow was found to depend primarily on the decay processes for the $1s_3$ species. Analysis of the pressure-dependent decay curve in the late afterglow has been carried out to derive the diffusion coefficient as well as two-body and three-body destruction frequencies for Kr $1s_3$ excited species. The diffusion coefficient was found to be 49 ${\mathrm{cm}}^2$ ${\mathrm{s}}^{-1\mathrm{}}$. The two-body collisional destruction rate was found to be 9×${10}^{-15\mathrm{}}$ ${\mathrm{cm}}^3$/s. The three-body collisional destruction rate, which presumably indicates the rate of formation of the excited dimer $\mathrm{Kr}_2^{}{}_{}{}^{*}$, was found to be 53.6×${10}^{-33\mathrm{}}$ ${\mathrm{cm}}^6$/s.