Taming the reaction dynamics of paramagnetic species

Project Information

RadiCool

Grant agreement ID: 948373

DOI

10.3030/948373

Project terminated on 31 May 2026

EC signature date 26 August 2020

Start date 1 January 2021

End date 30 September 2026

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 1 976 275,00

EU contribution

€ 1 976 275,00

Coordinated by

THE UNIVERSITY OF LIVERPOOL
United Kingdom

Periodic Reporting for period 4 - RadiCool (Taming the reaction dynamics of paramagnetic species)

Reporting period: 2024-01-01 to 2025-06-30

Summary of the context and overall objectives of the project

Radicals are paramagnetic species---atoms or molecules with an unpaired electron---and they are prevalent in gas-phase environments such as the atmosphere, combustion systems and the interstellar medium. In spite of their real-world importance, very few experimental methods can be applied to the precise study of gas-phase radical reactions. This is primarily due to the significant challenges associated with such studies; there are no established methods for generating a pure beam of atomic or molecular gas-phase radicals with tuneable properties. In this project, we provide a solution. We are developing a versatile and innovative “magnetic guide”, for the generation of a pure and state-selected beam of radicals. The magnetic guide will feature a series of specially-designed permanent magnets (Halbach arrays) and skimming blades. It will act as a stand-alone device, producing a pure beam of radicals with continuously tuneable velocity from a gas mixture (containing radicals, precursor molecules and seed gases). The magnetic guide will be combined with two existing experiments---an ion trap and a liquid-surface set-up---and will enable us to study ion-radical and radical-liquid surface interactions with unprecedented control and precision. Our measurements will provide the missing experimental data needed to improve the accuracy of (for example) complex atmospheric chemistry models---replacing untested predictions from capture theory calculations.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

A key element of this project is the development of a new magnetic guide device. A second-generation magnetic guide has been successfully designed, constructed, and characterised. This work was recently presented at a scientific meeting (International Symposium on Molecular Beams, Crete, June 2023) and is being prepared for publication. Other achievements related to the project include: the development and publication of a full three-dimensional self-consistent mean field DSMC (SCMFD) code; the formation of Coulomb crystals in the cryogenic ion trap; the optimisation of a Zeeman-decelerated and magnetic-guided radical beam; and the study of new reaction systems within Coulomb crystals.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The new magnetic guide device represents an exciting development in the control of molecular radical beams. We anticipate that we will be able to push beyond the current state-of-the-art by manipulating the internal energy distribution, the velocity, and the purity of radical beams. Following these final characterisation studies, we will use these radical beams to study ion-radical and radical-liquid surface interactions.