MOLECULAR UNIVERSE

The CRESU (Cinètique de Réaction en Ecoulement Supersonique Uniforme) apparatus (UR1), developed for the study of ion-molecule and neutral-neutral reactions at temperatures as low as 10 K, will be extended to study reactions of PAHs and energy transfer processes and product branching ratios. Further developments will focus on discharge and pulsed laser techniques for the production of excess concentrations of atomic radicals, the construction of nozzles for the use of H₂ as carrier gas for energy transfer studies and the implementation of additional detection techniques such as REMPI. These techniques are well complemented by new methods developed at Bordeaux to mboratory studies on chemical reactionseasure product branching ratios for reactions of atomic carbon at intermediate to low temperatures. The ion-trap methods (Toulouse III and Leiden)—where ions can be stored for long times at low temperatures and pressures—are uniquely suited to study slow processes (e.g. radiative association reactions) as well as the reactivity of photofragment ions such as dehydrogenated PAHs and (carbon) clusters. Molecular beam techniques (Bordeaux and Perugia)—using pulsed (Bordeaux) and continuous (Perugia) supersonic beams of neutral species and laser spectroscopy (Bordeaux) and mass spectroscopy (Perugia) for the detection of reagents and products—are unique in their capabilities to identify neutral-neutral reaction product(s). New laser ablation techniques will be included to produce intense beams of refractory elements (C-atoms, metals). By varying the relative orientation of the two sources, very low collision energies, appropriate for interstellar space, can be attained.