Crossed molecular beams study of inelastic non-adiabatic processes in gas phase collisions between sodium ions and ZnBr2 molecules in the 0.10-3.50 keV energy range

Inelastic electronically non-adiabatic reactions between Na+ ions and neutral ZnBr2 molecules, both in their electronic ground state, have been studied using crossed beams techniques and measuring the decaying emission radiation of the excited species produced. The fluorescent emission corresponding to Na(3 P-2) produced by a charge transfer reaction was observed, as well as that corresponding to the decay of Zn(4s 5s S-3), generated by dissociation of the neutral target molecule, to Zn(4s 4p P-3). The phosphorescent decaying emission of Zn*(4s 4p P-3) to the zinc ground state was also observed. For each emission process, the cross section energy dependences have been measured in the 0.10-3.50 keV energy range in the laboratory system. The ground electronic state of the (NaZnBr2)(+) collision system has been characterized by ab initio chemical structure calculations at the second order Moller-Plesset perturbation level of theory using pseudo-potentials. By performing restricted open shell Hartree-Fock calculations for C-2v geometries, four singlet and four triplet potential energy surfaces of the system have been calculated and used to interpret qualitatively the observed reactions. A simple two-state dynamical model is presented that allows an estimation of the maximum values for measured cross sections at high collision energies to be made. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4757967]