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O: Fachverband Oberflächenphysik

O 45: Mini-Symposium: Molecular scale investigations of liquid-vapor interfaces I

O 45.5: Talk

Tuesday, March 2, 2021, 15:10–15:30, R3

Imaging Gas-Liquid Scattering Processes in Real Space — •Maksymilian Roman, Robert Bianchini, Adam Knight, Daniel Moon, Kenneth McKendrick, and Matthew Costen — Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom

A novel technique for studying the dynamics of gas-liquid scattering was used to image the products of hydroxyl radical (OH) collisions with low-vapour-pressure liquids. A pulsed molecular beam of OH was aimed at layers of squalane, squalene and perfluoropolyether and probed by exciting laser-induced fluorescence (LIF) with pulsed laser light shaped into a sheet. The LIF signal emitted from pre- and post-collision packets of OH was intensified and captured by a camera. The images showed that OH scattered with broad angular distributions, but with superthermal speeds and rotational distributions, suggesting a predominantly impulsive mode of scattering from an atomically rough surface. The experiment has been recently modified to include a physically narrower ingoing packet of radicals and a better shaped laser probe sheet. Together with a custom-made Monte Carlo simulation of the scattering process, these are expected to provide even greater insight into the angular and speed distributions of the scattered products and hence the underlying scattering dynamics.