Probing the interstellar PAH hypothesis in electrodynamic traps

• Applicant: Professorin Sandra Brünken, Ph.D.
• Subject Area: Astrophysics and Astronomy
• Term: from 2011 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 203747251

The PAH hypothesis associates the unidentified infrared (UIR) emission bands observed in many astronomical environments to the fluorescence of large polycyclic aromatic hydrocarbons (PAHs) that are excited by the interstellar radiation field. The presence of PAHs in space is now widely accepted, as is their importance for the physics and chemistry of the interstellar medium (ISM). However, there are still many open questions related to details of the PAH hypothesis. One of the key issues regards the composition of the interstellar PAH family, since no single carrier of the observed IR bands could be identified so far. Here we propose highly sensitive IR and far-IR action spectroscopic studies of PAH ions in different hydrogenation and charge states to be compared to characteristics of the astronomical observations. Experiments will be carried out in temperature variable ion traps under conditions resembling those in the ISM.Another question concerns the formation and destruction of PAHs. We want to obtain high-resolution ro-vibrational and ultimately rotational spectra of small ionic fragments and building blocks of PAHs, which will support searches for these species with sensitive radio-telescopes like ALMA. These kinds of studies became feasible by our instrument and method development in the past years. Related to this we will study directly, by mass-spectroscopic means, the dissociation processes of PAH ions irradiated by visible and UV light.The long term perspective of this project is to understand the spectroscopy, photo-physics and chemistry of ionized PAHs and their building blocks.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1573: Physics of the Interstellar Medium
• Participating Person: Professor Dr. Stephan Schlemmer