Collisional transfer between the $6s^{\prime }{\left[\frac{1}{2}\right]}_{0,1}$ and $6p{\left[\frac{1}{2}\right]}_1$ xenon levels

The destruction rates of the xenon $6s^{\prime }{\left[\frac{1}{2}\right]}_0$ metastable and $6s^{\prime }{\left[\frac{1}{2}\right]}_1$ resonance atoms by collisions with ground-state xenon atoms have been measured by studying the temporal dependence of the number densities of the $6s^{\prime }$ and $6p$ atoms. The studies have been made both during the earlier afterglow of a xenon pulsed discharge and after the selective production of the $6s^{\prime }{\left[\frac{1}{2}\right]}_{0,1}$ atoms by a laser excitation in the late afterglow. An original optical pumping technique, using a tunable pulsed dye laser, was employed to populate the $6s^{\prime }{\left[\frac{1}{2}\right]}_{0,1}$ levels by excitation of the $6s{\left[\frac{3}{2}\right]}_2$ long-lived metastable atoms to $6p^{\prime }$ levels. The pressure dependence of the decay frequencies of these $6s^{\prime }{\left[\frac{1}{2}\right]}_{0,1}$ atoms was analyzed in the xenon pressure range of 0.04 to 1 torr and a kinetic model describing the evolution of the densities of these atoms after their production was established. The rate coefficients for the relaxation of the $6s^{\prime }{\left[\frac{1}{2}\right]}_0$ metastable and $6s^{\prime }{\left[\frac{1}{2}\right]}_1$ resonance atoms by two-body collisions involving a ground-state xenon atom are (8.45±0.85) × ${10}^{-12\mathrm{}}$ ${\mathrm{cm}}^3$ ${\sec }^{-1\mathrm{}}$ and (6.65 ± 1.00) × ${10}^{-11\mathrm{}}$ ${\mathrm{cm}}^3$ ${\sec }^{-1\mathrm{}}$, respectively. Results show that, in fact, at least 75% of this relaxation is a transfer of population to the $6p{\left[\frac{1}{2}\right]}_1$ level following ${\mathrm{Xe}}^{*}\left(6\mathrm{}{s}^{\prime }{\left[\frac{1}{2}\right]}_{0,1}\right)+\mathrm{Xe}\rightleftarrows {\mathrm{Xe}}^{*}\left(6p{\left[\frac{1}{2}\right]}_1\right)+\mathrm{Xe}-\Delta E$. These collisional transfer processes have been explained by means of Mulliken's xenon molecular potential curves.