Atom addition reactions in interstellar ice analogues

Abstract

This review paper summarizes the state-of-the-art in laboratory based interstellar ice chemistry. The focus is on atom addition reactions, illustrating how water, carbon dioxide and methanol can form in the solid state at astronomically relevant temperatures, and also the formation of more complex species such as hydroxylamine, an important prebiotic molecule, and glycolaldehyde, the smallest sugar, is discussed. These reactions are particularly relevant during the dark ages of star and planet formation, i.e., when the role of UV light is restricted. A quantitative characterization of such processes is only possible through dedicated laboratory studies, i.e., under full control of a large set of parameters such as temperature, atom-flux, and ice morphology. The resulting numbers, physical and chemical constants, e.g., barrier heights, reaction rates and branching ratios, provide information on the molecular processes at work and are needed as input for astrochemical models, in order to bridge the timescales typical for a laboratory setting to those needed to understand the evolutionary stages of the interstellar medium. Details of the experiments as well as the astrochemical impact of the results are discussed.

References in corpus (14)

• Formation of methyl formate and other organic species in the warm-up phase of hot molecular cores
• Testing grain-surface chemistry in massive hot-core regions
• Formation of hydrogen peroxide and water from the reaction of cold hydrogen atoms with solid oxygen at 10K
• Desorption of CO and O2 interstellar ice analogs
• Water Formation through a Quantum Tunneling Surface Reaction, OH + H2, at 10 K
• CO2 formation in quiescent clouds; an experimental study of the CO + OH pathway
• H-atom bombardment of CO2, HCOOH and CH3CHO containing ices
• Mobility of D atoms on porous amorphous water ice surfaces under interstellar conditions
• Molecular dynamics simulations of the ice temperature dependence of water ice photodesorption
• Interstellar Simulations Using A Unified Microscopic-Macroscopic Monte Carlo Model with a full Gas-Grain Network including Bulk Diffusion in Ice Mantles
• Formation of hydroxylamine on dust grains via ammonia oxidation
• Molecular dynamics simulations of D2O ice photodesorption
• On the relevance of the H2 + O reaction pathway for the surface formation of interstellar water - A combined experimental and modeling study
• Thermal H/D exchange in polar ice - deuteron scrambling in space