Chemical irradiation effects in ices

We present some chemical effects of the irradiation of ices by keV light ions. We have detected the synthesis of new compounds by means of in situ infrared spectroscopy. We discuss the results obtained by the irradiation of pure H2O or CH4 ices, as well as mixtures: (H2O+CO2); (H2O+NH3); (CO2+NH3). In all cases, we observe a rich variety of small species, not always unambiguously identified. Broad features are also generally present, which are likely the signature of more complex molecules. In some cases residues are formed, which are stable after annealing at room temperature. (orig.)