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

Abstract

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 θ inc = 60°] 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.