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Identifier

000453745

Title

Excitation dynamics of small molecules probed with velocity map imaging and time-resolved electron diffraction

Alternative Title

Δυναμική διέγερση μικρών μορίων ανινχνεύσιμα με απεικόνιση ιόντων και χρονοεξαρτημένη περίθλαση ηλεκτρονίων

Author

Γιαννακίδης, Ιωάννης

Thesis advisor

Παπάζογλου, Δημήτριος

Reviewer

Σαμαρτζής, Πέτρος
Βελεγράκης, Μιχάλης

Abstract

In this thesis we report on velocity map imaging (VMI), photoelectron circular dichroism (PECD), and time-resolved electron diffraction (TRED) experiments on the excitation dynamics of small molecules. In the first part we explore high energy (9−10eV) laser excitation of C2H2 which results in generation of C2H+ 2 and C2H+, C+ 2 , C+ and H+ photofragments. We present VMI images and the resulting kinetic energy release and angular distributions of the ion and photoelectrons products. The underlying mechanisms generating those photoproducts are discussed. In the second part we report chirality detection of structural isomers in a gas phase mixture using nanosecond photoelectron circular dichroism (PECD). Combining pulsed molecular beams with resonance enhanced multi-photon ionization (REMPI) allows detection of the target enantiomer in the presence of other chiral molecules. More specifically we demonstrate detection of fenchone enantiomers (S or R) in the presence of camphor enantiomers (S or R) and vice versa. The third part of this thesis presents the construction and first experimental tests of a time-resolved electron diffractometer. We describe the design and construction of a high-brightness electron gun, a position-sensitive detector, and the vacuum system that contains them all. We also present our first characterization experiments on the electron gun pulses.

Language

English

Subject

Chiral molecules

Photodissociation dynamics

Δομική δυναμική

Δυναμική φωτοδιάσπασης

Χειρόμορφα μόρια

Issue date

2023-03-29

Collection

School/Department--School of Sciences and Engineering--Department of Materials Science and Technology--Post-graduate theses