Partial differential cross sections for inelastic He++Ne collisions at low energy

Abstract

Abstract. We report differential cross section measurements with high angular resolution for different channels of the inelastic processes He + + Ne --+He + + Ne* and He + + Ne ~ He* + Ne +, for collision energies between 100 and 200 eV. For the Ne states (2p53s)~'3p1, which decay optically, we determined the fraction with the alignment at right angles to the scattering plane. The results are used to discuss the mechanism of the processes and the influence of the spin--orbit interaction upon the collision.

Numerical treatment of inelastic He++Ne collisions at low energy

“…As the first coupling term is of the order of h2/2m, a 2 (m~ the electron mass), the third one is negligible. Note that this conclusion holds only for states that obey (13). Other states, for instance the eigenstates of H~, can vary much more rapidly, leading to large values of the third coupling term.…”

“…The oscillatory structure of these curves are Rosenthal oscillations. The data are compared with the corresponding experimental results [13,151 . The frequency of the Rosenthal oscillations is reproduced quite satisfactorily.…”

“…8 the probability p~ to find the He + spin inverted (from my = -1/2 to my = + t/2 or vice versa) after a collision leading to Ne(2p53s) 1p~ or 3P 1 excitation. The data are compared with the experimental results [13]. The experimental cross sections in Fig.…”

“…When the spin-orbit interaction is without influence, He + spin inversion can occur only by electron exchange. It is then related to the triplet fraction T as follows [13] p~i = T / ( 6 -47').…”

“…Even for apparently simple systems such as H + He or H + Na, no calculations have been reported for energies below 100 eV (H + He) or 1 keY (H + Na). The present work deals with the He + + Ne system in the 100 eV range, because a considerable amount of experimental data is available for this system ( [13] and references therein). The numerical methods applied are expected to be valid at lower energies as well.…”