Infrared Resonant Vibrationally Induced Restructuring of Space Relevant Ices

Formation and destruction of simple and complex organic molecules in the solid phase in space is strictly linked to the physicochemical conditions at play. In the dense cold interstellar medium, dust particles are covered by polar and apolar ice layers that act as catalytic surfaces toward a higher molecular complexity. External triggers such as impinging atoms, photons, electrons and ions inject energy in a processed layer causing physical and chemical changes within the ice. To fully understand processes such as molecular diffusion, reaction, and desorption, it is therefore fundamental to investigate energy transfers mechanisms under interstellar conditions. In this talk, I will present recent experimental results on hydrogen bonding irreversible changes in water-rich ices induced by the intense, nearly monochromatic mid-IR and THz FEL radiation of the FELIX 1 and 2 beamlines. Experiments are carried-out by means of the ultrahigh vacuum (UHV) Laboratory Ice Surface Astrophysics (LISA) end-station designed and operated by my group at FELIX Laboratory. Current analytical tools of LISA are Fourier Transform Infrared spectroscopy and quadrupole mass spectrometry. Experiments are complemented by Molecular Dynamics simulations to constrain the effect at the molecular level.