Multiple fragmentation dynamics after laser excitation: A simple theoretical approach

A model to describe molecular fragmentation into several fragments is prese nted. The case where dissociation is induced by the absorption of a single or several photons from ultrashort pulses is considered. Time-dependent per turbation theory is employed to describe the excitation process and the sub sequent fragmentation dynamics is treated using various theories treating d irect and indirect break-up processes. The multiple fragmentation of the Fe (CO)(5) molecule serves as a numerical example. Different experiments are s imulated and, regarding the simplicity of the model, an overall excellent a greement between theory and experiment is found, thus providing an insight into the excitation and fragmentation dynamics under various conditions. (C ) 2001 American Institute of Physics.