Light-Field Controlled Molecular Reactions

Informations projet

LFC-MORE

N° de convention de subvention: 886046

DOI

10.3030/886046

Projet clôturé

Date de signature de la CE 23 Mars 2020

Date de début 1 Septembre 2020

Date de fin 31 Août 2022

Financé au titre de

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Coût total

€ 175 572,48

Contribution de l’UE

€ 175 572,48

Coordonné par

STICHTING RADBOUD UNIVERSITEIT
Netherlands

Periodic Reporting for period 1 - LFC-MORE (Light-Field Controlled Molecular Reactions)

Période du rapport: 2020-09-01 au 2022-08-31

Résumé du contexte et des objectifs généraux du projet

It is a long-held dream of physical chemists to get a complete understanding of chemical reactions, and to ultimately even fully control them. Traditional ways to manipulate the outcome and yield of such reactions include altering the temperature and pressure for the reaction, or adding a catalyst. In a bottom-up approach, a chemical reaction can be seen as a collision or interaction between a molecule and, for instance, an atom, another molecule, or light. The aim of this project was to control half-collisions between molecules and light using an electric field provided by a powerful laser. During the project, however, we realized that this was even more challenging than expected. Instead, we worked towards controlling collisions between two molecules or a molecule and an atom. We used a Zeeman decelerator to manipulate the velocity and quantum state of carbon atoms, and let them collide with helium atoms or hydrogen molecules in a controlled way. After the collision, we detected the scattered products using advanced detection techniques. This powerful combination of techniques allowed us to investigate these collision processes in high detail. Afterwards, we started investigating controlled reactive collisions between sulfur atoms and hydrogen molecules. Our experimental approach allows us to investigate these reactions in extremely high detail. In the future we hope to fully control and determine the outcome of such reactions.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

We started using a new experimental machine, and tested it by studying the photodissociation of oxygen molecules. We looked into different product channels and developed a new detection scheme for oxygen atoms in the ground state. The results of this study were published in a peer-reviewed journal.

Afterwards, we started working with the Zeeman decelerator to investigate molecular collisions in a controlled way. We managed to manipulate the velocity and quantum state of carbon atoms, and to detect them with low recoil velocities in order to be able to perform high-resolution scattering studies. We did this by implementing a VUV-based near-threshold ionization scheme. When we were able to control and detect the carbon atoms well, we investigated controlled inelastic collisions between these atoms and helium atoms or hydrogen molecules. We could precisely tune the collision energy, and investigate the outcome of the collision as function of energy. We did this by recording the angular scattering distributions of the scattered carbon atoms. The first results are published in a peer-reviewed journal, and further results will be published in the future.

We also investigated inelastic collisions in different systems, and were able to get a better understanding of specific molecular dynamics underlying the scattering process. Some results are already published in a peer-reviewed journal, and another paper will be written in the near future.

For the last part of this project, we for the first time investigated reactive collisions between sulfur atoms and hydrogen molecules using our experimental approach. Investigating reactive scattering is even more challenging than inelastic scattering, but we managed to see the first signals and to record the first angular scattering distributions of the reaction products. We developed new analysis methods and implemented new ways to record the data, in order to be able to extract more information from the measurements. We will continue this research after the end of this project.

The results of this project were disseminated in several publications, and more publications are on the way. Moreover, results were presented at multiple national and international conferences. In addition, the researcher gave guest lectures at a high school and seminars for students to engage a broader audience for our research. She will moreover participate in an upcoming Open Day of the faculty, where the public can visit the lab.

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

We found an efficient ionization scheme for detecting oxygen (O) atoms in the ground state, which is very promising for future studies on scattering systems involving O-atom products in various labs around the world. We implemented a recoil-free VUV based detection method in scattering experiments involving a decelerator and velocity map imaging. Moreover, we for the first time used our Zeeman decelerator for reactive scattering studies. We expect that our experimental approach can lead to a much better understanding of chemical reactions, and that we will in the future be able to precisely control the outcome of reactions.

Impression of a controlled chemical reaction