Non-Sticking of Helium Buffer Gas to Hydrocarbons

TL;DR

This paper estimates the lifetimes of helium-hydrocarbon complexes at low temperatures, showing they are short and decrease with larger hydrocarbons, indicating clustering won't hinder helium buffer gas spectroscopy.

Contribution

It introduces a density-of-states approach to estimate complex lifetimes and compares results with classical trajectory data, providing new insights into helium buffer gas interactions.

Findings

Lifetimes are less than 10-100 ns for helium-hydrocarbon complexes.

Lifetimes decrease as hydrocarbon size increases.

Clustering is unlikely to limit precision in helium buffer gas spectroscopy.

Abstract

Lifetimes of complexes formed during helium-hydrocarbon collisions at low temperature are estimated for symmetric top hydrocarbons. The lifetimes are obtained using a density-of-states approach. In general the lifetimes are less than 10-100 ns, and are found to decrease with increasing hydrocarbon size. This suggests that clustering will not limit precision spectroscopy in helium buffer gas experiments. Lifetimes are computed for noble-gas benzene collisions and are found to be in reasonable agreement with lifetimes obtained from classical trajectories as reported by Cui {\it et al}.