Photodissociation Dynamics Of Randomly Oriented Molecular Ensembles By Time-Resolved Electron Diffraction

The introduction of time in diffraction methods and the development of foundational principles of their analysis opens up new methodologies to study transient states of the reaction centers, and short-lived intermediate compounds in gaseous and condensed media. In the current article, we propose the basic elements of the theory that can be employed in analyses of TRED data recorded from randomly oriented laser-excited molecules. The formalism is applicable to photodissociative processes and to nuclear dynamics studies of photodissociation phenomena. The theory was illustrated by modeling the diffraction intensities of photogenerated dissociation of ICN molecules. Based on model calculations presented in this article we conclude that, by TRED method, time-dependent coherent dissociation dynamics can in principle be resolved at a realistic time scale that significantly shorter than the electron pulse duration of 300 fs, which is achieved at present in a number of TRED experiments.