Reaction geometry from orbital alignment dependence of ion pair production in crossed-beam Ba(1P1)–Br2 reactions

Abstract

Strong orbital alignment dependence was observed for Ba⁺ produced in crossed‐beam reaction of Ba(¹P₁) with Br₂. The peak of this dependence varied strongly with scattering angle for alignment of the p orbital in the scattering plane, with the maximum flux seen for perpendicular alignment with respect to the relative velocity vector. The measured Ba⁺ was always favored by alignment of the orbital in the scattering plane, regardless of laboratory scattering angle. The experimental results suggest that this charge‐transfer process is dominated by large impact‐parameter collisions which achieve collinear nuclear geometry and Σ orbital alignment at the crossing point. Orbital locking is probably not important owing to the large internuclear distance of the crossing region.