Velocity Map Imaging the Scattering Plane of Gas Surface Collisions

TL;DR

This paper introduces a novel velocity map imaging technique for gas-surface collisions, enabling detailed 2D velocity distribution measurements of scattered molecules, which was previously limited by technical challenges.

Contribution

It presents an innovative method to incorporate a surface into a velocity map imaging setup, maintaining optimal imaging conditions for gas-surface scattering studies.

Findings

Successful measurement of velocity distributions of scattered ammonia molecules.

Demonstrated retention of velocity mapping conditions with a new surface integration approach.

Validated the method with measurements across multiple rotational states.

Abstract

The ability of gas-surface dynamics studies to resolve the velocity distribution of the scattered species in the 2D sacattering plane has been limited by technical capabilities and only a few different approaches have been explored in recent years. In comparison, gas-phase scattering studies have been transformed by the near ubiquitous use of velocity map imaging. We describe an innovative means of introducing a surface within the electric field of a typical velocity map imaging experiment. The retention of optimum velocity mapping conditions was demonstrated by measurements of iodomethane-d3 photodissociation and SIMION calculations. To demonstrate the systems capabilities the velocity distributions of ammonia molecules scattered from a PTFE surface have been measured for multiple product rotational states.