Detailed studies of the reactions of electronically excited IBr[E(0+)] with Xe, translationally excited Xe(3P2) with I2, Br2 and ICl, and Kr(3P2) with Br2 are reported. Vibrationally excited levels in the E(0+) ion-pair state of IBr were pumped using tunable synchrotron radiation and the ‘vibrational’ excitation function for XeBr(B) formation determined for energies 66 kJ mol–1 above threshold. Branching ratios for XeBr(B)vs. XeI(B) formation, together with data for the alternative excitation-transfer channel have also been determined over the same energy range. Fully dispersed chemiluminescence spectra and their polarizations have been measured under superthermal atomic beam [Xe(3P2), Kr(3P2)]–Maxwellian gas (I2, Br2, ICl) conditions at average collision energies Ēcm < 120 kJ mol–1. These have revealed distinctive patterns of behaviour for the collisional energy dependence of branching into alternative atom- and excitation-transfer channels and of vibrational energy and rotational angular momentum disposals. A simple global model is presented to reconcile the varying patterns of behaviour found in the rare-gas–halogen systems under both ‘collisional’ and ‘complexed’ conditions, and in particular the dependence on the initial reagent state preparation.