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Abstract:

Understanding the evolution and behavior of interstellar ices is essential for interpreting molecular observations in astrophysical environments. This talk presents two complementary studies conducted at the Photoprocessing and Spectroscopy Laboratory, simulating space-like conditions using ultra-high vacuum and cryogenic technologies. The first study investigates how photon-induced desorption contributes to the presence of volatile molecules in the gas phase within dense molecular clouds. By examining the evolution of ices under energetic irradiation—from cold molecular clouds to protoplanetary disks—we highlight the critical role of absorption cross-sections in the solid phase. This perspective helps explain the discrepancies reported in photodesorption yields across different experimental groups. The second study focuses on the interaction between interstellar ices (CO, CO2, and H2O) and carbonaceous dust grains. Using temperature-programmed desorption (TPD), we found that porous amorphous carbon enhances molecular trapping and alters desorption dynamics, especially for CO and CO2. In contrast, H2O remains largely unaffected by substrate differences due to strong intermolecular hydrogen bonding. These findings underscore the importance of dust grain properties in shaping ice behavior and survival in cold astrophysical environments. These studies provide deeper insight into the physical and chemical processes governing interstellar ices, with implications for astrochemical modeling and observational interpretation.