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Collisional and Half-Collisional Dynamics of Conformationally Selected Molecules

English title Collisional and Half-Collisional Dynamics of Conformationally Selected Molecules
Applicant Willitsch Stefan
Number 188329
Funding scheme South Korea
Research institution Physikalische Chemie Departement Chemie Universität Basel
Institution of higher education University of Basel - BS
Main discipline Physical Chemistry
Start/End 01.01.2020 - 31.12.2023
Approved amount 313'050.00
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All Disciplines (2)

Discipline
Physical Chemistry
Other disciplines of Physics

Keywords (7)

Stark deflection; Reaction Dynamics; Photochemistry; Spectroscopy; Molecular physics; Conformers; Chemical physics

Lay Summary (German)

Lead
Die Geschwindigkeit und der Mechanismus von chemischen Reaktionen sind oft von der Struktur der zugrundeliegenden Moleküle beeinflusst. Sogar kleinste Änderungen der Molekülstruktur können manchmal grosse Veränderungen im chemischen Verhalten hervorrufen. Es ist daher notwendig, sowohl intra- als auch inter-molekulare chemische Prozesse in einem integrierten Ansatz gemeinsam zu untersuchen, um zu einem vertieften Verständnis des Zusammenhangs zwischen Molekülstruktur und chemischer Reaktivität zu gelangen. Das gegenwärtige Projekt zielt auf eine detaillierte Charakterisierung dieser Abhängigkeiten in ausgewählten Modellsystemen basierend auf der komplementären Expertise der Schweizer und Koreanischen Projektpartner ab.
Lay summary
Im gegenwärtigen Projekt werden sowohl strukturelle als auch quantenmechansiche Aspekte der Dynamik und der Mechanismen von ausgewählten chemischen Reaktionen unter präzise kontrollierten Bedingungen in der Gasphase untersucht. Komplexe Moleküle liegen unter Umgebungsbedingungen üblicherweise als eine Mischung von verschiedenen strukturellen Varianten, sogenannten Konformeren, vor. In diesem Projekt werden die betreffenden Moleküle in Molekülstrahlen eingebracht und deren Konformere mithilfe von elektrischen Feldern räumlich aufgetrennt, so dass es möglich ist, deren individuelle Reaktivität gezielt zu untersuchen. Hierbei wird sich der koreanische Partner auf intra-molekulare Prozesse wie die strukturabhängige Fragmentierung der Moleküle unter Einfluss von Laserlicht konzentrieren, während der Schweizer Partner inter-molekulare Prozesse wie reaktive Stösse untersuchen wird. Spezifisches Ziel dieser Untersuchungen werden organische Moleküle wie Hydrochinon, Resorcinol und Oxalylchlorid und deren Reaktionen mit freien Radikalen sein. 

Diese Projekt unternimmt zum ersten Mal eine konzertierte Untersuchung der Strukturabhängigkeit von intra- und inter-molekularer chemischer Reaktivität in den selben Modellsystemen unter präzise kontrollierten Bedingungen. Wir erhoffen uns dadurch ein integriertes Bild vom Zusammenhang zwischen Molekülstruktur und Reaktivität zu gewinnen, welcher vielen chemischen Prozessen zugrundeliegt.
 
Direct link to Lay Summary Last update: 10.10.2019

Responsible applicant and co-applicants

Gesuchsteller/innen Ausland

Employees

Name Institute

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Physical Chemistry Seminar (online) Individual talk Cold molecular ions in traps:
From molecular quantum technologies to precise mechanistic studies of chemical reactions 12.11.2021 University of Berkeley , United States of America Willitsch Stefan;


Associated projects

Number Title Start Funding scheme
189907 Controlled reactive collisions with trapped ions 01.01.2020 COST (European Cooperation in Science and Technology)
204123 Quantum technologies for molecular precision spectroscopy 01.01.2022 Project funding
157874 Conformationally controlled chemistry 01.09.2015 SNSF Consolidator Grants

Abstract

The reaction rates and dynamics of chemical reactions and molecular energy transfer are often influenced by the structure of the involved molecules. Even subtle changes of the molecular geometry can make significant differences in chemical reactivity. Both intramolecular and intermolecular processes need to be understood on the quantum level in molecular systems with well-defined geometries in order to establish a detailed understanding of structure-reactivity relationships. The present project aims at establishing a comprehensive characterisation of these relationships in selected model systems by studying both collisional and half-collisional reactions by pooling the expertise of the Korean and Swiss partners. Combined structural and quantum aspects of chemical reaction dynamics will be studied under precisely controlled conditions in the gas phase. State-of-the-art experimental techniques such as Stark deflection, double-resonance, stimulated-emission pumping and hole-burning will be employed in order to spatially or spectroscopically isolate specific conformational isomers of the molecules in the gas phase. This will enable the study of half-collisional reactions such as photodissociation, intramolecular tunnelling, and isomerization as well as state-selective full collisional reactions in a conformer-specific manner. Measurements of conformationally resolved spectra and reaction-rate constants will be complemented by frequency and/or time resolved velocity-map ion/electron imaging experiments to elucidate fine details of the reaction dynamics. The systems targeted in this study are hydroquinone, resorcinol and oxalyl chloride and their reactions with free radicals such as F, Cl and OH which have been selected for their prototypical character and experimental amenability. In addition to the bare conformationally selected molecules, investigations will also be performed with their conformationally selected clusters with water in order to study the effects of incipient solvatisation on the reactivity and dynamics. Moreover, vibrationally state-selected studies will be performed to gain insights into the interplay between mode- and structure-specific reactive effects. The experiments will be complemented by ab-initio and reactive molecular dynamics calculations to analyse and interpret the data.Spectroscopic characterization of conformers and their half-collisional dynamics will be studied at KAIST in Korea, whereas full collisional dynamics involving conformer-specific neutral-radical will be investigated at University of Basel in Switzerland. The partner groups constitute an ideal match to carry out the present research programme by sharing similar research interests, but contributing complementary scientific expertise, techniques and equipment. The project relies on harvesting the synergies between the groups through the exchange of knowledge, of experimental techniques and of data as well as through the joint training of PhD students and regular scientific visits of the involved personnel between Switzerland and Korea.By for the first time contrasting intra- with inter-molecular dynamics in selected geometry-selected model systems, we expect that the present project will yield new and valuable insights into structure-reactivity relationships in chemistry. We expect that the present results will not only be of immediate relevance for the advancement of molecular and chemical physics, but will also contribute to the general understanding of chemical reactivity and be of specific benefit to a wider range of disciplines such as synthetic chemistry and catalysis.
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