The population transfer between excited $3p^{5}4p$ argon levels induced by the collisional process. ${\mathrm{Ar}}^{*}{\left(3\mathrm{}{p}^{5}4p\right)}_i+\mathrm{Ar}\left({}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}\right)\rightleftarrows {\mathrm{Ar}}^{*}{\left(3\mathrm{}{p}^{5}4p\right)}_j+\mathrm{Ar}\left({}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}\right)+\Delta E$ was studied in the afterglow of an argon pulsed discharge, at the pressure range of 0.2-1 Torr. Selective population of one particular argon $3p^{5}4p$ level was achieved by laser excitation from one metastable state by use of a tunable cw dye laser. The populations of the laser-excited level and of the collisional excited levels were determined by intensity measurements of the fluorescence line and of the sensitized fluorescence lines. The time-dependence study of the population of the metastable state, of the laser-excited state, and of the collisional excited states was carried out to ascertain the product channel and to determine the collisional transfer rate coefficients.

• Received 5 May 1978

DOI:https://doi.org/10.1103/PhysRevA.18.1388