Evidence for Rb-Rare-Gas Molecules from the Relaxation of Polarized Rb Atoms in a Rare Gas. Experimental Results

Relaxation experiments have been performed between 0–200 G on optically polarized Rb atoms in argon, krypton or xenon, at pressures ranging from 0.1 to 20 torr. They clearly show the existence of $\mathrm{Rb}–\mathrm{Ar},\mathrm{Rb}–\mathrm{Kr}$ and $\mathrm{Rb}–\mathrm{Xe}$ molecules of low binding energy (smaller than kT). Molecular parameters such as lifetime, spin‐orbit coupling constant, formation rate, constant of mass action, etc., are measured, or evaluated when they cannot be directly measured. Experimental values of the diffusion coefficient of Rb in the gas (except xenon) and of the disorientation cross sections by usual binary collisions are also obtained.