Elastic and rotationally inelastic scattering of fluorine atoms by deuterium molecules at 112 meV collision energy

Abstract

The F+D 2 elastic scattering as well as the D 2( j i=0 → j f=2), D 2( j i=1 → j f=3) and, for the first time, D 2( j i=0 → j f=4) inelastic rotational transitions have been measured in a crossed molecular beam experiment at a center-of-mass collision energy of 112±2 meV. Differential cross-sections for the measured rotational transitions have been calculated on three different potential energy surfaces (Takayanagi–Sato, DMBE-6SEC of Truhlar and coworkers, and Stark–Werner) using different quasiclassical and semiclassical techniques. Although an overall qualitative agreement is found between the experimental and computed differential cross-sections, significant discrepancies are also apparent. In particular, the dynamical calculations lead to a systematic underestimation of the scattering yield into the non-reactive scattering channels, which can be attributed to shortcomings in the topography of all the three surfaces probed. Replacing the free deuterium molecule with a rigid or a vibrating rotor (both of these models exclude reaction) in the dynamical treatment considerably reduces the disagreement between the experimental and the calculated differential cross-sections for the different inelastic transitions.