Infrared free-electron laser irradiation of carbon dioxide ice

Interstellar ice grains are believed to play a key role in the formation of many simple and complex organic species detected space. However, fundamental questions on physicochemical processes linked survival remain unanswered. Field work at large-scale facilities such as free-electron lasers (FELs) can aid investigation composition morphology by providing novel tools laboratory astrophysics community. We combined high tunability, wide infrared spectral range intensity FEL beam line FELIX-2 HFML-FELIX Laboratory The Netherlands with characteristics ultrahigh vacuum LISA end station perform wavelength-dependent mid-IR irradiation experiments space-relevant pure carbon dioxide (CO2) 20 K. used intense monochromatic radiation FELIX inject vibrational energy selected frequencies into CO2 study restructuring effects situ Fourier Transform Reflection–Absorption Infrared (FT-RAIR) spectroscopy. This improves our understanding how introduced external triggers photons, electrons, cosmic rays, thermal heating coming from nascent protostar or field stars is dissipated an interstellar icy dust grain Moreover, it adds current literature debate concerning amorphous polycrystalline structure observed upon deposition low temperatures, showing that, under experimental conditions, presents when deposited K unambiguously crystalline if 75