Rotational quenching of monofluorides in a cryogenic helium bath

TL;DR

This study investigates the collision dynamics and transport properties of monofluoride molecules in cryogenic helium, providing insights into their rotational quenching behavior relevant for buffer gas cooling techniques.

Contribution

It offers a comprehensive quantum chemistry and dynamics analysis of monofluoride-He interactions, elucidating the physics of rotational quenching in buffer gas cooling.

Findings

Calculated interaction potentials using ab initio methods.

Analyzed thermalization and rotational quenching rates.

Explained quenching physics via Born Distorted Wave Approximation.

Abstract

Buffer gas cooling, one of the most relevant direct cooling techniques for cooling molecules, relies on dissipating the energy of the molecule via collisions with a buffer gas. The cooling efficiency hinges on the molecule-atom scattering properties, concretely, on the transport properties. This work presents a global study on the interactions, collision dynamics, and transport properties of monofluoride molecules (X-F), being X a metal, in the presence of a cold He buffer gas. The interactions are calculated using ab initio quantum chemistry methods, and the dynamics is treated fully quantal, assuming the monofluoride molecule is a rigid rotor. The resulting thermalization and rotational quenching rates are analyzed in light of the Born Distorted Wave Approximation (BDWA), yielding an explanation based on the elemental physical properties of the molecule under consideration. Therefore, the analysis of our results reveals the physics behind the rotational quenching of molecules in the presence of a cold buffer gas.