ORBITAL ALIGNMENT DEPENDENCE AND ANGULAR-DISTRIBUTIONS OF IONS FROM THE REACTION OF BA(S-1,P-1) WITH CL2

We report crossed molecular beam studies of positive ions produced in the reaction of ground-state and electronically excited barium atoms with Cl2 at collision energies of 0.75 and 3.0 eV. At 0.75 eV, angular distributions for BaCl+ from the exothermic chemi-ion channel were largely backscattered relative to the barium beam. For Ba(1P), the cross section for BaCl+ formation was much lower at both collision energies studied. At 3.0 eV the product Ba+ was observed, and the yield increased 20-fold on electronic excitation. In addition, the Ba+ intensity was further enhanced 2-fold when the barium p orbital was aligned along the relative velocity vector over that seen with the p orbital perpendicular to the relative velocity vector. © 1990 American Chemical Society.