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Abstract: Since many years, the Laboratory for Experimental Astrophysics in Catania (Italy) has given a contribution to a number of experiments with the aim to investigate the physico-chemical effects induced by fast ions irradiating astrophysical relevant materials. Here, we review some of the most recent results, namely irradiation of mixtures of solid CO and S-bearing molecules. In the interstellar medium, two or more icy compounds can coexist to form ice mantles on grains in two different forms: either they can be mixed together or form separated layers (ice segregation). Thus experiments have been performed with targets prepared at low T (15–20 K) both by a co-deposition of a mixture of two gas compounds (CO and SO2 or H2S) and with targets prepared by deposition of CO ices on a previously deposited SO2 or H2S layer. Samples have been irradiated with 200 keV protons with the aim of simulating a cosmic ion bombardment of interstellar ices. The results show that new chemical species are formed; in particular, OCS and CS2. The astrophysical relevance of the results is discussed.

A large variety of carbon rich macromolecules has been studied in our laboratory, before, during, and after ion irradiation (3‐60 keV ions), by in situIR and Raman spectroscopies. In this paper we present results obtained on: (a) Films of frozen H2O:CH4:N2mixtures that have been deposited at low temperature (12 K) on a silicon substrate, and irradiated with fast ions. Irradiation causes the formation of organic refractory residues whose spectra have been recorded and studied also after further irradiation at room temperature. (b) Pentacene (a Polyciclic Aromatic Hydrocarbon, PAH) whose Raman spectra have been studied also during ion irradiation at room temperature. (c) Thin samples of fullerene (C60) films also irradiated at room temperature.

Silicates are one of the principal components present in Solar System objects.Silicates evolve in space modifying their physical properties according to theastronomical environments they go through. To characterise the nature of TNOsin the framework of the formation and evolution of the Solar System, experimentson structural transitions of silicates have been performed in the laboratoryto simulate some of the processing suffered by the dust. The infrared spectralproperties of possible silicate candidates thought to be present in TNOs have beenstudied. The results of thermal annealing of amorphous silicates and amorphisationof crystalline forsterite (pure-Mg olivine) by ion irradiation are presented. Theobservable properties of TNOs surfaces are inferred.

We have obtained infrared spectra of planetary nebulae in the 3.0–3.8 µm range using IRSPEC, the ESO grating infrared spectrograph, attached to the 3.6-m telescope. We find evidence of an evolution of the carriers of the unidentified emission bands in the 3 µm region, and explain the observed behaviour in terms of ion irradiation from fast stellar wind.

From the frontiers of research on ice dynamics in its broadest sense, this review surveys the structures of ice, the patterns or morphologies it may assume, and the physical and chemical processes in which it is involved. Open questions in the various fields of ice research in nature are highlighted, ranging from terrestrial and oceanic ice on Earth, to ice in the atmosphere, to ice on other Solar System bodies and in interstellar space. [ABSTRACT FROM AUTHOR]