Direct observation of product-pair correlations in rotationally inelastic collisions of ND3 with D2

Abstract

We present a combined experimental and theoretical study of state-to-state inelastic scattering of ND₃(j^±_k = 1₁⁻) with D₂ (j = 0, 1, 2, 3) molecules at collision energies around 800 cm⁻¹. Using a crossed molecular beam apparatus which employs the combination of Stark deceleration and velocity map imaging, we observe the correlated rotational excitations of both collision partners. For D₂, both elastic (Δj_D2 = 0), inelastic excitation (j = 0 → j = 2) and inelastic de-excitation (j = 2 → j = 0) processes are observed. For a number of final ND₃ states, inelastic channels in which D₂ is rotationally excited or de-excited appear surprisingly strong. The experimental results are in excellent agreement with the predictions from quantum scattering calculations which are based on an ab initio ND₃–D₂ potential energy surface.