EFFECTS OF ATOMIC ORIENTATION ON ATOM-DIMER EQUILIBRIA IN ALKALI-METAL VAPORS

Optical orientation of reagents is one approach to achieving selectivi ty in a chemical reaction and has been used successfully to shift the point of equilibrium in bulk reaction mixtures of alkali-metal atoms a nd dimers. In addition to the continuous control of the point of equil ibrium in the dimerization of sodium atoms, the control of the ortho-p ara nuclear spin distribution is shown here to also be a function of t he degree of atomic spin orientation over a broad range. The direction of the spin conversion is para to ortho. For a multicomponent vapor, the optical orientation of Li-6 in a mixture of lithium-6 and lithium- 7 is shown to produce a continuous and selective control of the isotop ic dimer concentrations. Li-6(2) (para) is selectively destroyed in th e presence of the other dimer species. In this way the composition of a multicomponent metal vapor system at chemical equilibrium can be man ipulated. The constraint produced by the optical orientation of one of the reagents offers a technique whereby the equilibrium yield of a mu lticomponent bulk chemical reaction can be laser controlled in a selec tive and continuous fashion.