Formation and Dissociation of Hydrocarbons Under Interstellar Conditions

Hydrocarbons of all shapes and sizes are found throughout the various stages of star- and planet formation. Recently, using radio astronomical observations, a variety of cyclic- and even polycyclic hydrocarbons have been detected in the very cold (10 K) Taurus molecular cloud. These detections challenge our understanding of the chemical formation mechanisms under these low-temperature and low-density conditions. In photon-dominated regions, on the other hand, very large Polycyclic Aromatic Hydrocarbons (PAHs) of 50 carbon atoms and larger are commonly detected as a class based on the characteristic mid-infrared emission bands that they emit after being electronically excited by ultraviolet and optical radiation. These large PAHs are exposed to a very strong radiation field that can alter their molecular structure and may even lead to dissociation. In this seminar, I will show how experimental studies using synchrotron and free electron laser radiation – in conjunction with quantum chemical computations – allow us to reveal the formation and dissociation mechanisms of interstellar (aromatic) hydrocarbons at a molecular level of detail.

Dr. Bouwman obtained a degree in applied physics from the Technische Hogeschool Rijswijk and then pursued a master’s degree in chemistry with specialization “laser sciences” at the Free University in Amsterdam. He then continued his career at Leiden University, where in 2010 he obtained his PhD degree in the field of laboratory astrochemistry under supervision of Prof. Harold Linnartz. He then moved to the University of California, Berkeley to do postdoctoral research in the group of Prof. Dr. Stephen Leone. After spending three years at the synchrotron of Lawrence Berkeley National Laboratory and on the UC Berkeley campus, in 2013, he moved to the Free Electron Laser Facility FELIX, at Radboud University in Nijmegen, the Netherlands, to conduct independent research on a personal grant. In 2016 he became an assistant professor at Leiden University. In 2021 he started a new position as an assistant professor of cosmochemistry at CU Boulder in the Laboratory for Atmospheric and Space Physics and the Chemistry Department. Dr. Bouwman's main interests over the years have been in understanding the formation and the dissociation of interstellar aromatic molecules using a combination of physicochemical laboratory techniques and quantum chemical calculations.