State-resolved inelastic and reactive scattering dynamics of gases with liquid surfaces

Energy transfer dynamics between gas and liquid surfaces are investigated by colliding a molecular beam of CO$_{2}$ with low vapor pressure liquids in vacuum. Nascent quantum states of CO$_{2}$ are probed via direct infrared absorption of the $\nu_{3}$ asymmetric stretch with a Pb-salt diode laser. The high spectral resolution ($\sim $20 MHz) of the laser provides the means to characterize the translational, rotational, vibrational, and angular distributions of the scattered CO$_{2}$. Experiments have probed an array of collision energies, incident and final scattering angles, liquids, and surface temperatures. In each case, multi-channel dynamics have been observed and characterized as trapping-desorption (TD) and impulsive scattering (IS). Rotational and translational distributions show considerable excitation above the surface temperature (T$_{S})$, while the vibrational distributions remain colder than T$_{S}$. Similar experiments have probed the HF(v,J) product from reactive scattering of fluorine atoms with a hydrocarbon surface. Both the inelastic and reactive scattering distributions are well-characterized by a two-temperature model where T$_{TD} \quad \sim $ T$_{S}$ and T$_{IS} \quad >$ T$_{S}$.