A ‘hot-spot’ model for impulsive scattering at the gas–liquid interface

Scattering of jet-cooled molecules by non-metallic liquids, and molecular dynamics simulations of scattering by self-assembled-monolayers (SAMs) lead to remarkably similar values of the rotational and translational temperatures of the scattered molecules. We explore whether this might reflect a transient equilibration of the molecules with microscopic ‘hot-spots’ created by the collision. Calculations of surface temperature for non-metallic liquids and SAMs as a function of time and distance from the impact suggest that collisions with the randomly bumpy surface should result in similar rotational and translational temperatures of the scattered molecules, but the high thermal conductivity of liquid metals makes such ‘hot spots’ too short-lived to be relevant.