Decay of krypton 1s2 and 1s3 excited species in the late afterglow

Experimental investigations of the behavior of the Kr 1s2 excited-state population in after-glow discharge plasmas are described. The number density of Kr 1s2 atoms was obtained by performing resonant absorption measurements at 8509 (Kr1s2→2p4) with a tunable GaAs laser diode. The narrow-width laser was tuned and swept through the entire resonant transition. The decay of the 1s2 species in the late afterglow was found to depend primarily on the decay processes for the 1s3 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 1s3 excited species. The diffusion coefficient was found to be 49 cm2s-1. The two-body collisional destruction rate was found to be 9×10-15 cm3/s. The three-body collisional destruction rate, which presumably indicates the rate of formation of the excited dimer Kr2*, was found to be 53.6×10-33 cm6/s.