Our knowledge of the interstellar medium (ISM) has grown rapidly in the last years, thanks to an unprecedented rate of molecular detections, followed by efforts from theory, experiments and kinetic models. These observations revealed that interstellar chemistry is far more complex and fascinating than expected, marked by constant chemical processing due to formation, evolution, and destruction of molecules in different environments. These processes occur in gas-phase and on interstellar grains, revealing a complex interplay that is almost always out of thermodynamic equilibrium. This results in an exotic chemistry, entangled to the physical conditions of the ISM and the presence of high-energy particles, with several species that would be unstable in Earth atmosphere.

Despite observational progress, the broad astrochemical community is still far from a comprehensive understanding of how chemistry evolves in star forming regions from diatomic to organic molecules, the latter being possible precursors of life. Furthermore, our understanding of the links between molecular abundances and processes during the stages of planetary system formation is rather fragmented and limited.

This Research Topic intends to act as an interdisciplinary platform to share state-of-the art research from all vertexes of the astrochemical canvas including observations, experiments, models, and theoretical simulations, considering also different interstellar regions, from diffuse molecular clouds to protoplanetary disks. To give a few examples, we aim to include experimental and computational study of chemical reactivity in gas and grain, observations of complex chemistry in dark clouds and derivation of collisional rate coefficients. Each of these activities is crucial and mandatory for a thorough interpretation of the chemistry in the ISM, and complements the other in some cases. Thus, this collection aims to reflect the multifaceted reality of astrochemistry and highlight the role each activity plays in understanding the chemical processes that shape the universe.

Contributions from different areas of astronomy, physics, and chemistry focusing on one or more of the following themes are welcome:

• Spectroscopic characterization of molecules
• Computational simulations for spectroscopy
• Laboratory studies on interstellar ice chemistry and dust grains
• Experimental and computational investigations into gas-phase reactions
• Theoretical modeling of interstellar ices and their chemistry
• Astrochemical kinetic models
• Modeling of chemical reactivity and molecular evolution
•Chemical composition and physical properties of interstellar clouds
• Search for new species in the ISM.

Submission in these fields and their interplay are strongly encouraged in form of original research. However, mini-reviews and reviews on one of the above topics are crucial to analyze the current gaps and guide future research. This Research Topic welcomes submission in all possible article formats.

Are you interested in contributing a manuscript to this Research Topic?

Refining the Interstellar Chemical Complexity: From Molecules to Models