Vector correlations in dissociative photoionization of diatomic molecules in the VUV energy range

The (VA+,Ve,P) vector correlation method for the study of dissociative photoionization (DPI) of a diatomic molecule AB, induced by linearly polarized synchrotron radiation (P), is presented. On the experimental side, imaging and time resolved coincidence techniques are combined to measure the VA+ and Ve velocity vectors for each DPI event. The information derived from the ion-electron kinetic energy correlation, and from the spatial analysis of the vector correlation, is illustrated on specific examples of dissociative photoionization of NO and O2 following excitation of inner-valence electrons in the 20–25 eV photon energy range. Based on the general form of the molecular frame photoelectron angular distributions (MFPAD) reported here for linear molecules excited by linearly polarized light, we discuss in particular the new information gained from the azimuthal dependence of the I(θ,φ) distribution, for each orientation of the molecular axis with respect to the polarization. The measured MFPADs are compa...