Photoelectron-photofragment coincidence studies of dissociation dynamics

Important insights into the energetics and dynamics of transient molecules and clusters have been obtained from studies of the photodetachment of negative ions. When photodetachment produces a neutral in a metastable or dissociative state, further information can be obtained by studying the subsequent dissociation dynamics of the molecule. This can be done by measuring the photoelectron kinetic energy and the photofragment translational energy release in coincidence. Energy- and angle-resolved measurements of this type are now possible in photoelectron-photofragment coincidence experiments. The photoelectron-photofragment coincidence technique is reviewed and the dissociative photodetachment (DPD) dynamics of O-4(-), O-3(-), NO-(N2O) and N3O2- are discussed. These systems provide examples of direct and sequential DPD processes, along with applications to the study of isomeric forms of molecular and cluster anions.