SE835: Computational astrochemistry: From the spectroscopy and formation of PAHs to interstellar photochemistry

Newly developed computational methods now allow for the disentanglement of the CD and CN stretches of deuterated and cyano-substituted polycyclic aromatic hydrocarbons (PAHs) in astronomical IR spectra from the James Webb Space Telescope. Gas-phase PAHs are ubiquitous forms of carbonaceous matter spread throughout the universe, and their emission, along with that of dust, is thought to dominate the near- and mid-IR spectrum of various astronomical sources such as protoplanetary disks and galaxies. To better understand the nature of this emission, advanced anharmonic quantum chemical methods in concert with high-resolution experiments at the FELIX research institute have been used to explore the spectroscopic characteristics of PAHs. Additionally, new formation mechanisms are proposed for the production of cyanobenzene, the smallest cyano-substituted aromatic molecule thus far detected in space, in the atmosphere of Titan, Saturn’s largest moon. Finally, excited state photochemistry reveals the (in)stability of small complex organic molecules in the harsh radiation fields of interstellar space and molecular clouds.