Thermal desorption of interstellar ices: a review on the controlling parameters and their implications from snowlines to chemical complexity

Laboratory astrophysics and astrochemistr

Rap, Nat. Astron.

This dataset contains data for the article "Low-temperature nitrogen-bearing polycyclic aromatic hydrocarbon formation routes validated by infrared spectroscopy". It includes the source data of several figures, i.e. the recorded experimental and calculated IR spectra, and the results of quantum-chemical calculations as log files.Abstract:Polycyclic aromatic hydrocarbons (PAHs) are abundant in many regions of the Universe, representing a major reservoir for cosmiccarbon. However, their formation pathways in cold regions of space remain elusive. Recent astronomical detections showthat current astrochemical models drastically underestimate the abundance of aromatic molecules and suggest that additionalformation pathways such as ion–molecule reactions need to be considered. Here we reveal efficient low-temperature formationpathways towards nitrogen-containing polycyclic aromatic hydrocarbons via exothermic pyridine+ and acetylene ion–moleculereactions. The experimental approach combines kinetics with spectroscopic probing and unambiguously identifies key reactionintermediates and the final nitrogen-containing polycyclic aromatic hydrocarbon product quinolizinium+, a structure that isthought to contribute to the 6.2 μm interstellar emission feature. This study not only provides competing formation pathwaysrelevant in the chemistry of the interstellar medium and Titan's atmosphere, but also delivers information to verify in-silicopotential energy surfaces, astrochemical models and infrared observations