Correlations in rotational energy transfer for NO-D-2 inelastic collisions

摘要

We present a combined experimental and theoretical study of state-to-state inelastic collisions between NO (X-2 Pi (1/2), j = 1/2, f) radicals and D-2 (j = 0, 1, 2, 3) molecules at collision energies of 100 cm(-1) and 750 cm(-1). Using the combination of Stark deceleration and velocity map imaging, we fully resolve pair-correlated excitations in the scattered molecules. Both spin-orbit conserving and spin-orbit changing transitions in the NO radical are measured, while the coincident rotational excitation (j = 0 -> j = 2) and rotational de-excitation (j = 2 -> j = 0 and j = 3 -> j = 1) in D-2 are observed. De-excitation of D-2 shows a strong dependence on the spin-orbit excitation of NO. We observe translation-to-rotation energy transfer as well as direct rotation-to-rotation energy transfer at the lowest collision energy probed. The experimental results are in good agreement with cross sections obtained from quantum coupled-channels calculations based on recent NO-D-2 potential energy surfaces. The observed trends in the correlated scattering cross sections are understood in terms of the NO-D-2 quadrupole-quadrupole interaction.