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 cosmic
carbon. However, their formation pathways in cold regions of space remain elusive. Recent astronomical detections show
that current astrochemical models drastically underestimate the abundance of aromatic molecules and suggest that additional
formation pathways such as ion–molecule reactions need to be considered. Here we reveal efficient low-temperature formation
pathways towards nitrogen-containing polycyclic aromatic hydrocarbons via exothermic pyridine+ and acetylene ion–molecule
reactions. The experimental approach combines kinetics with spectroscopic probing and unambiguously identifies key reaction
intermediates and the final nitrogen-containing polycyclic aromatic hydrocarbon product quinolizinium+, a structure that is
thought to contribute to the 6.2 μm interstellar emission feature. This study not only provides competing formation pathways
relevant in the chemistry of the interstellar medium and Titan's atmosphere, but also delivers information to verify in-silico
potential energy surfaces, astrochemical models and infrared observations.