Some consequences of atomic orientation in electron-atom scattering by consideration of attractive and repulsive forces

Discusses some consequences of the classical grazing model of Kohmoto and Fano (1981) to the problem of atomic orientation by electron collisions. The authors introduce amplitudes for repulsive and attractive scattering interactions and related them to the magnetic sublevel; amplitudes f 0 and f 1 of the coherent 1 S to 1 P excitation process. An important consequence of the grazing model is a left-right asymmetry in the scattering of electrons having excited the atom with a given definite orientation. It follows from parity invariance that the circular polarisation of the 1 P to 1 S radiation emitted perpendicular to the scattering plane is identical to the left-right intensity asymmetry of the scattered electrons measured in coincidence with right- and left-hand circularly polarised light. The magnitudes and the phase difference of the amplitudes for attractive and repulsive interactions of the coherent 1 S to 1 P excitation can be calculated from the knowledge of the lambda and chi parameters.