Stereodynamics in state-resolved scattering at the gas–liquid interface

Stereodynamics at the gas-liquid interface provides insight into the important physical interactions that directly influence heterogeneous chemistry at the surface and within the bulk liquid. We investigate molecular beam scattering of CO(2) from a liquid perfluoropolyether (PFPE) surface in vacuum [incident energy E(inc) = 10.6(8) kcal/mol, incident angle theta(inc) = 60 degrees] to specifically reveal rotational angular-momentum directions for scattered molecules. Experimentally, internal quantum state populations and M(J) distributions are probed by high-resolution polarization-modulated infrared laser spectroscopy. Analysis of J-state populations reveals dual-channel scattering dynamics characterized by a two-temperature Boltzmann distribution for trapping-desorption and impulsive scattering. In addition, molecular dynamics simulations of CO(2) + fluorinated self-assembled monolayers have been used to model CO(2) + PFPE dynamics. Experimental results and molecular dynamics simulations reveal highly oriented CO(2) distributions that preferentially scatter with "top spin" as a strongly increasing function of J state.