Interstellar complex organic molecules (iCOMs) can be loosely defined as chemical compounds with at least six atoms in which at least one is carbon. The observations of iCOMs in star-forming regions have shown that they contain an important fraction of carbon in a molecular form, which can be used to synthesize more complex, even biotic molecules. Hence, iCOMs are major actors in the increasing molecular complexity in space and they might have played a role in the origin of terrestrial life. Understand-ing how iCOMs are formed is relevant for predicting the ultimate organic chemistry reached in the interstellar medium. One possibility is that they are synthesized on the interstellar grain icy surfaces, via recombination of previously formed radicals. The present work focuses on the reactivity of HCO with CH3/NH2 on the grain icy sur-faces, investigated by means of quantum chemical simulations. The goal is to carry outa systematic study using different computational approaches and models for the icy surfaces. Specifically, DFT computations have been bench-marked with CASPT2 and CCSD(T) methods, and the ice mantles have been mimicked with cluster models of 1, 2, 18 and 33 H2O molecules, in which different reaction sites have been considered. Our results indicate that the HCO + CH3/NH2 reactions, if they actually occur, have two major competitive channels: the formation of iCOMs CH3CHO/NH2CHO, or the formation of CO + CH4/NH3. These two channels are either barrierless or presentrelatively low ($\leq$ 10 kJ/mol equal to about 1200 K) energy barriers. Finally, we briefly discuss the astrophysical implications of these findings.
JWST Observations of Young protoStars (JOYS+): Detection of icy complex organic molecules and ions. I. CH$_4$, SO$_2$, HCOO$^-$, OCN$^-$, H$_2$CO, HCOOH, CH$_3$CH$_2$OH, CH$_3$CHO, CH$_3$OCHO, CH$_3$COOH
Cis--Trans Rotational Isomerism of Seleno-, Thio-, and Formic Acids and Their Dimers: Chemical Kinetics under Interstellar Conditions
Department of Analytical, Biopharmaceutical and Medical Sciences, ATU, Galway, Ireland（爱尔兰高威应用科技大学分析、制药与医学科学系）；School of Biological & Chemical Sciences, University of Galway, Galway, Ireland（爱尔兰高威大学生物与化学科学学院）
Isotopomer-Specific Carbon Isotope Ratio of Complex Organic Molecules in Star-Forming Cores
National Astronomical Observatory of Japan（日本国立天文台）；The Graduate University for Advanced Studies, SOKENDAI（综合研究大学院大学）；RIKEN Cluster for Pioneering Research（理化学研究所前沿研究集群）；The University of Tokyo（东京大学）；Queen’s University Belfast（贝尔法斯特女王大学）
