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

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*(3 p) system over the collision energy range E_c.m.=50-100 eV. We communicate the optimal alignment angle γ and linear polarisation P_l⁺ of the charge cloud as well as its relative height ρ₀₀ and the angular momentum L_⊥⁺ transferred in the collision as a function of the scattering angle. For preparation of the sodium 3 p orbital in the scattering plane (positive reflection symmetry) we observe that at small reduced scattering angles (<20 eV°) the preparation of a pσ at large internuclear distances contributes most to the scattering intensity whereas at larger reduced scattering angles (>60 eV°) a pπ⁺ preparation is more important. In contrast, preparation of the pπ^- 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.