Radiofrequency multipole traps: Tools for spectroscopy and dynamics of cold molecular ions

TL;DR

This paper reviews the use of multipole radiofrequency ion traps, especially cryogenic 22-pole traps, as versatile tools for studying cold molecular ions, their reactions, and spectroscopy in controlled environments.

Contribution

It provides a comprehensive tutorial on radiofrequency multipole ion trapping, discussing stable trapping, cooling methods, heating mechanisms, and recent experimental applications.

Findings

Effective trapping and cooling of molecular ions at cryogenic temperatures.

Insights into ion-molecule reaction dynamics and spectroscopy.

Future research directions in multipole ion trap technology.

Abstract

Multipole radiofrequency ion traps are a highly versatile tool to study molecular ions and their interactions in a well-controllable environment. In particular the cryogenic 22-pole ion trap configuration is used to study ion-molecule reactions and complex molecular spectroscopy at temperatures between few Kelvin and room temperatures. This article presents a tutorial on radiofrequency ion trapping in multipole electrode configurations. Stable trapping conditions and buffer gas cooling, as well as important heating mechanisms, are discussed. In addition, selected experimental studies on cation and anion-molecule reactions and on spectroscopy of trapped ions are reviewed. Starting from these studies an outlook on the future of multipole ion trap research is given.