Chemistry in the Interstellar medium

    Although popularly considered as a perfect vacuum, the space between stars presents a very rich and exotic chemistry. As new telescopes are being developed and improved, new intriguing molecules have been detected in a variety of conditions, ranging from interstellar clouds to star forming regions and circumstellar envelopes. 

    This is an interdisciplinary field by nature. Astronomers observe the sky and detect new molecular species and their abundances in different regions. Laboratory experiments simulate reactions between these molecules, and account for their reactivity. Theoretical chemistry can simulate the extreme conditions that occur in space, explain the underlying mechanisms of laboratory reactions, and even predict the outcomes of reactions that are difficult to tackle experimentally. Research under these lines allows for a better understanding of the evolution of the interstellar medium. Particularly important is the mass growth processes that lead to grains and ultimately to planetary systems formation.

    In this talk, we will review stellar life cycles to highlight in what conditions molecules can be observed. The exotic properties of interstellar chemistry and the currently observed molecules will be presented. After this introduction, results from our group and in collaboration with astronomers and experimentalists on several important reactions will be given. Their impact on explaining the evolution of molecular abundances will also be highlighted. From a computational chemistry perspective, the work encompasses high level multireference calculations, description of the potential energy surface of ground and excited electronic states and reaction dynamics to predict rate coefficients, through quasiclassical trajectories and statistical approaches.

 

References

¹M. A. M. Paiva, B. Lefloch, B. R. L. Galvão,  Mon. Not. R. Astron. Soc., 481, 1858 (2018)

²M. A. M. Paiva, B. Lefloch, B. R. L. Galvão, Mon. Not. R. Astron. Soc. 493, 299–304 (2020)

³S. Doddipatla, C. He, S. Goettl, R. I. Kaiser, B. R. L. Galvão,  T. J. Millar, Sci. Adv. 7, eabg7003 (2021).

⁴C. He, Z. Yang, S. Doddipatla, L. Zhao, S. Goettl, R. I. Kaiser, M. X. Silva, B. R. L. Galvão, J. Phys. Chem. Lett. 12, 2489 (2021)

Acknowledgements

This work has been financed by CNPq, CAPES and CEFET-MG. Computational resources from Santos Dumont supercomputer are also acknowledged.