Dinámica y estereodinámica de la fotodisociación de moléculas y radicales por tomografía láser de imágenes de iones

Abstract

The aim of the present work is to unravel the photodisociation dynamics of two molecular systems, methyl iodide (CH3I) and nitromethane (CH3NO2), and one radical system, the allyl radical (C3H5). The study has been carried out using the Velocity Map Imaging (VMI) and the Slice imaging (Slicing) techniques, that allow us to determine a set of experimental observables which provide detailed information about the elemental mechanism of the dissociation process. This memory is divided into two distinct parts. The rst part is devoted to the stereodynamical characterization of the photodisociation of methyl iodide (CH3I) and nitromethane (CH3NO2) through the determination of the di erent vector correlations that describe the process. In order to achieve that purpose, we have adapted the methodology work published by Grubb et al. [1, 2], which connects the bipolar moments of Dixon, 2 0(20), 0 0(22), 2 0(02), 2 0(22) [3] with the anisotropy parameters, i, obtained from VMI or Slicing of the di erent fragments produced in the dissociation process. The bipolar moments of Dixon, 2 0(20), 0 0(22), 2 0(02) and 2 0(22), describe, respectively, the vector correlations {u100000} v; v {u100000} J; {u100000} J and {u100000} J {u100000} v, where is the transition dipole moment, v the relative velocity of the recoiling photofragments and J is the total angular momentum of the considered photoproduct. The determination of the asymptotic correlation between these vectors gives insight into the underlying dynamics of the reaction revealing the excited state symmetry and couplings, the dissociation time-scales, and details about forces and torques between the departing fragments.