Simulation of M₂⁺ alkali molecules embedded in neon clusters: Structures, spectroscopic properties, nonadiabatic dynamics

The purpose of this thesis is to study the properties of M₂⁺ alkali molecules embedded in neon clusters, by means of numerical simulations. We developed a comprehensive approach in which the electronic structure determination is reduced to a one-electron problem. The electron evolves in a potential modelled by semi-local core polarization potentials. Their parametrization was completed after we performed ab initio calculations of the potential energy curves of MNe and M⁺Ne dimers. We carry out a classical molecular dynamic, including a nonadiabatic coupling treatment, by means of a surface hopping algorithm. We found equilibrium geometries of the M₂⁺Ne_n systems, up to the first solvation shell of the molecule. We deduced the static properties of these systems, investigating binding energies, equilibrium distances and optical absorption spectra. Then, we studied the dynamics of these systems, initially promoted to an excited state. We established that photo fragmentation yield highly depends on the number of neon atoms and on electronic transition ordering. We observed a cage effect for M₂⁺Ne_n systems for n≥18. We also performed analysis of product fragment distribution, stabilized molecular states and electronic charge localization in asymmetrical systems. (author)