IR characterization and radiation chemistry of glycolaldehyde and ethylene glycol ices

Motivated by detections of glycolaldehyde and ethylene glycol in the interstellar medium and, for ethylene glycol, in comet Hale-Bopp, we report the low-temperature mid-IR spectra of these two molecules, including selected band strengths and positions. Each molecule has also been irradiated with 0.8 MeV protons to simulate cosmic-ray exposure, to measure each molecule's radiation lifetime, and to determine radiation chemical products. Evidence is presented that glycolaldehyde is readily formed from irradiated ethylene glycol ices, both in the presence and absence of H2O ice.