Dynamique de systèmes polyatomiques et polyélectroniques en champ laser intense

Authors: Dion, François
Advisor: Nguyen-Dang, Thanh-Tung
Abstract: This thesis deals with the dynamics of molecules in intense laser fields in the quasi-static picture. Two types of dynamics are considered, namely the dynamics of nuclear motions, i.e. vibrations and molecular dissociations, in the first part of the thesis, and the dynamics of electronic motions, excitations and ionization of a N-electron molecule, in the second part. In the first part, we will be concerned particularly about a vibrational trapping mechanism called Dynamical Dissociation Quenching (DDQ), applicable in the quasi-static regime, and two objectives in this respect are set: The generalization of the concept for strong-field induced dynamical structural changes to polyatomic molecules, and the search for optimal conditions for the control of the molecule/field synchronization that underlies the DDQ effect. To this end, new parameters are explored, among them is a laser frequency chirp, and a set of parameters defining a proper pump-probe setting and deduced from properties of the mean trajectory of the field-free vibrational wavepacket. In the second part of the thesis, a methodology recently developed for the computation of multiconfigruation wavefunctions describing a N-electron system interacting with an ulrashort, intense laser pulse, is used to describe the dynamics of electronic excitations and ionization of the linear molecule CO2 in an intense Infra-red laser pulse. Emphasis is placed on manyelectron, many-orbital effects on momentum (velocity) distributions of the photoelectron, and more specifically, on the Laser-Induced Electron Diffraction (LIED) spectra, as well as on their robustness under molecule/field misalignment.
Document Type: Thèse de doctorat
Issue Date: 2018
Open Access Date: 9 July 2018
Permalink: http://hdl.handle.net/20.500.11794/30325
Grantor: Université Laval
Collection:Thèses et mémoires

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