Electronic excitation processes in the collisional system

Electronic excitation processes in the collisional system NaRb+ in the energy range 0.1–5.0 keV have been studied by means of a crossed molecular beam technique and measuring the fluorescent emission of the excited species formed, these being Na(32P12,32), Na(72S12), Na(62D52,32), Na(52D52,32) and Na(42D52,32). For all of them the total excitation cross-section dependence on collision energy (c.e.) has been determined. In addition, the first one has been resolved in its J components, the branching ratio having a value c.e.-independent and close to the statistical one. Also, by polarization anisotropy measurements the Na(32S12)→Na(32P32) excitation cross section has been resolved into its MJ components, whose c.e. dependence shows possible interference effects at low c.e. Results for this first excitation have been interpreted both in terms of a linear Landau-Zener-Stückelberg model and of the evolution of quasi-diabatic molecular orbitals of the NaRb+ quasi-molecule obtained by ab initio calculations.