Alignment and orientation effects in resonant charge exchange from laser excited Na*(3p)

Abstract

A collisional alignment and orientation study with planar symmetry is described, determining the complete density matrix for resonant charge transfer from laser excited atoms. Results are reported for the Na++Na*(3p) system over the collision energy rangeEc.m.=50−100 eV. We communicate the optimal alignment angle γ and linear polarisationPl+ of the charge cloud as well as its relative height ρ00 and the angular momentumL⊥+ transferred in the collision as a function of the scattering angle. For preparation of the sodium 3p orbital in the scattering plane (positive reflection symmetry) we observe that at small reduced scattering angles ( 60 eV°) apπ+ preparation is more important. In contrast, preparation of thepπ− orbital (perpendicular to the scattering plane) is large at small and vanishes at larger scattering angles. We conclude that orbital following cannot be assumed in this resonant charge transfer process. The angular momentum transfer is observed to be small, indicating only little coherence in the process, but shows nevertheless an interesting behaviour as a function of scattering angle.