Atom-molecule scattering: Classical simplicity beneath quantum complexity

Analysis of scattering angle (theta(p)) versus velocity for (A) (1) Sigma(u)(+)Li(2)-Xe inelastic collisions reveals the process in classical rather than quantal terms. The parallel component of velocity is scattered unchanged and the perpendicular component is converted into molecular rotation. For each Delta j channel, the only perpendicular component is upsilon(th), the channel-opening velocity. Hence direction of the incident velocity and scattering angle are determined by a vector relationship with upsilon(th) and upsilon(r)(i) cos theta(p), the perpendicular and parallel components of upsilon(r)(i), respectively. The results suggest classical relations underly the complexities of quantal scattering with momentum disposal the guide to outcome.