Velocity dependence of rates for rotationally inelastic collisions in Na*2–Xe using velocity selection by Doppler shift

Abstract

We have measured the velocity dependence of rotational energy transfer (RET) rate constants for Na^*₂(A ¹Σ_u⁺)–Xe collisions over an order of magnitude range in relative kinetic energy. Measurements were made for initial rotational levels j_i=16, 38, and 66 for four different values of Δ=j_f−j_i. The present data are analyzed in terms of the energy corrected sudden (ECS) scaling approximation and determine the velocity dependence of both the ’’adiabatic correction’’ factor of the ECS theory, and the parameters a and γ which appear in the power law expression for the basis rates k_l→0(v_r) =a(v_r)[l(l+1)]^−γ(v_r), an expression shown to be valid at all relative velocities studied. These measurements were made in a gas cell using the velocity selection by Doppler shift (VSDS) technique. Full details of analysis and deconvolution procedures used to isolate the relative velocity dependence are given.