Carbonaceous matter is exchanged between planetary systems and the interstellar medium during the death-and-rebirth cycle of stars, and its journey is revealed through unique spectroscopic fingerprints across the electromagnetic spectrum. Yet, many of these spectroscopic features remain elusive. Identifying them holds the key to unveiling interstellar chemical intricacies, constraining extraterrestrial carbon life cycles, and deciphering the initial phases of chemical evolution. However, obtaining laboratory data under conditions that allow comparison with astronomical observations has proved to be a major experimental challenge, not to mention the wide range of possible molecular carriers. Carbon cages such as C₆₀, C₇₀, and C₆₀⁺, known for their high photostability, have been ubiquitously detected in extraterrestrial environments. The next larger detected molecule possesses only 25 carbon atoms. To bridge this knowledge gap, it is necessary to obtain gas-phase spectral fingerprints of wisely selected large carbon-rich molecules. Our instrument integrates state-of-the-art mass spectrometry and ion mobility spectrometry with advanced laser spectroscopic techniques, resulting in an innovative experimental setup. The instrument provides spectroscopic signatures ranging from the near-infrared to the ultraviolet, for meticulously selected molecular ions, enabling direct comparisons with astronomical data.

Interstellar molecular clouds host a rich organic chemistry that gives rise to increasingly complex molecules, including aromatic species that are considered key intermediates in the formation of prebiotic matter. However, current astrochemical models largely rely on isomer-averaged descriptions, neglecting the crucial influence of molecular structure on reaction pathways and product branching ratios. The aim of this work is to determine the branching ratios of reaction products arising from atomic carbon addition to key intermediates involved in the growth of aromatic molecules in space, and to elucidate the structures of the resulting aromatic species. These experimental results will be complemented by quantum chemical calculations and kinetic modeling to provide a detailed mechanistic understanding of the underlying processes and to improve the predictive power of astrochemical models.

A major limitation of current astrochemical models and chemical reaction networks is the lack of isomer-specific kinetic data and structural identification of reaction products. Experimental constraints on chemical networks are often difficult to obtain because the most thermodynamically stable isomer is not necessarily the most chemically reactive one. Reactive isomers are frequently produced in low abundances, rapidly isomerize into more stable structures, or are challenging to isolate under laboratory conditions. Consequently, their intrinsic reactivity and associated rate coefficients remain poorly characterized. As a result, many reactions are either omitted from astrochemical networks or represented by isomer-averaged rate constants, introducing substantial uncertainties into model predictions. You will take part in the development of an instrument that combines ion mobility and mass spectrometry with laser spectroscopy in order to address the critical challenges aforementioned.