Effects of atomic orientation on atom-dimer equilibria in alkali-metal vapors

Abstract

Optical orientation of reagents is one approach to achieving selectivity in a chemical reaction and has been used successfully to shift the point of equilibrium in bulk reaction mixtures of alkali-metal atoms and dimers. In addition to the continuous control of the point of equilibrium in the dimerization of sodium atoms, the control of the ortho-para nuclear spin distribution is shown here to also be a function of the degree of atomic spin orientation over a broad range. The direction of the spin conversion is para to ortho. For a mutlicomponent vapor, the optical orientation of ${}^{6}\mathrm{Li}$ in a mixture of lithium-6 and lithium-7 is shown to produce a continuous and selective control of the isotopic dimer concentrations. ${}^{6}{\mathrm{Li}}_{2}$ (para) is selectively destroyed in the presence of the other dimer species. In this way the composition of a multicomponent metal vapor system at chemical equilibrium can be manipulated. The constraint produced by the optical orientation of one of the reagents offers a technique whereby the equilibrium yield of a multicomponent bulk chemical reaction can be laser controlled in a selective and continuous fashion.