A model to describe molecular fragmentation into several fragments is presented. The case where dissociation is induced by the absorption of a single or several photons from ultrashort pulses is considered. Time-dependent perturbation theory is employed to describe the excitation process and the subsequent fragmentation dynamics is treated using various theories treating direct and indirect break-up processes. The multiple fragmentation of the Fe(CO)(5) molecule serves as a numerical example. Different experiments are simulated and, regarding the simplicity of the model, an overall excellent agreement between theory and experiment is found, thus providing an insight into the excitation and fragmentation dynamics under various conditions.