The effect of spin-orbit coupling upon elastic collisions between alkali atoms

V. V. Batygin, Dmitriy V. Kupriyanov

J. M. M. J. Vogels, B. Verhaar, R. H. Blok

Philip George Burke, John F. Mitchell

An analysis of spin-polarization in low energy elastic scattering electrons by one electron s-state atoms is carried out allowing both for electron exchange and relativistic effects. First the collision matrix is written in terms of the asymptotic form of the solutions of the radial equations. Then arguments, based on the invariance of the Hamiltonian under time reversal, space rotation and space reflection are used to write down the most general form of this matrix. It is found that it can be expressed in terms of six independent amplitudes. Then expressions for the observable quantities, including the spin polarization of the electron and of the atom after the collision are derived. Finally, the analysis is specialized to the case where spin-polarization effects are caused by a spin-orbit interaction and these effects are considered in the neighbourhood of cusps and resonances in electron alkali atom scattering.

Michael J. Redmon

E. E. Nikitin, M. Ya. Ovchinnikova

The influence of an external magnetic field upon the depolarisation cross section of the 2 P 1/2 state of the alkalis in collisions with noble-gas atoms is estimated for a strong spin-orbit coupling ( Delta epsilon >>h(cross)/ tau 0 , mu e B, where Delta epsilon is the spin-orbit splitting of the 2 P j doublet, tau 0 is the collision time and mu e B is the Zeeman splitting). The relative correction to the depolarisation cross sections appears to be less than 10 -2 (B/10 kOe) 2 . This casts serious doubts on the suggested interpretation of the experimentally found large-field effect.

E. I. Dashevskaya, A. Voronin, E. E. Nikitin