MOLECULAR ALTERATION AND CARBONIZATION OF GLYCINE BY ION IRRADIATION

A set of experimental results obtained by irradiating glycine (C2H5O2N) with 3 ke V He ions is presented. The technique used to get an insight into the induced processes is in situ IR spectroscopy. Evidence of ion-induced decrease in the intensity of the IR molecular bands is shown. Probably this is due to molecular (H-2, NH3, CO2) desorption. The decrease in the band intensities becomes approximately zero after a fluence of approximately 5.10(16) ions cm-2. It is likely that this behaviour is due to progressive carbonization of the target. If we assume that the decrease is entirely due to a loss of the corresponding molecules, then the atomic concentration from the initial C:O:N = 0.4:0.4:0.2 varies to an asymptotic value of C:O:N = 0.82:0.18: approximately 0. Some possible astrophysical implications of the results are also suggested.