Circular polarisation measurements of the Lα cascade radiation for the 32Dj states of atomic hydrogen, excited by electron impact

Measurements are reported for the circular polarisation of the Lα radiation arising from the cascade of the 32Dj states of atomic hydrogen to the 22Pj states detected in coincidence with electrons with n = 3 energy loss. Data for the atomic orientation parameter L perpendicular are presented at incident electron energies of 54.4 and 100 eV and at scattering angles θe of 200 and 250. These data, together with previous measurements for this transition, constitute a determination of the complete parameter set {γ, P1, ρ00, L perpendicular} for 32Dj excitations in this dynamic range. Calculations for P3 and L perpendicular using distorted-wave approximation theory are also performed. The theoretical results are presented and compared with the experimental data. (author)