Momentum transport cross sections for excited and ground state potassium with rare gases by light-induced diffusive pulling

Abstract

We have used the light-induced diffusive pulling (LDP) method to measure the ground state momentum transport cross sections and the relative difference of the excited and ground state cross sections with respect to the ground state for potassium with several inert gas atoms. For the LDP measurements, the excited state cross section is a weighted average of the potassium 4'P,/, and 4'P,/, fine structure levels, which are mixed by collisions with the inert gas atoms. We have also used a light-induced drift (LID) experiment to measure the ratio of the differences in the excited and ground state cross sections for the individual fine stmcture levels (Au(3 = 5) : A u ( J = 1)) for potassium-Ne and patassium-Ar. For the case of potassium-Ar, we have combined this ratio with the results from the LDP measurements to obtain absolute transport cross sections for the individual 4'S,/,, 4'P,,, and 42P3/2 levels.

Diffusion cross sections for potassium and levels in rare gases

“…We then use a four-level velocity-dependent rate equation model to extract the ratio of cross sections, R s as defined above. Combining these results with the ground-state cross sections and averaged σ/σ g reported by Mugglin et al (1992), we also report the absolute cross sections for the individual 4 2 P 1/2 and 4 2 P 3/2 levels. We also report calculated cross sections, based on available theoretical potential curves, using the theory of Reid (1975), as adapted for momentum transfer cross sections by Hickman et al (1993).…”

“…for K in Ar and Ne by comparing light-induced drift velocities (Mugglin et al 1992). (We will use J = 1 2 and J = 3 2 in the argument of σ to refer to the D 1 and D 2 transitions.)…”