Speaker
Dr
Sandra Brünken
(Universität zu Köln)
Description
Sandra Brünken and Stephan Schlemmer, I. Physikalisches Institut, Universität zu Köln, Germany
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. Whereas the presence of PAHs in space is now widely accepted, there are still many open questions related to the 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. In this project we want to perform highly sensitive IR and far-IR action spectroscopic laboratory studies of PAH ions in different hydrogenation and charge states to be compared to astronomical observations. Experiments will be carried out on mass-selected, cold PAH ions in temperature variable ion traps. Here we will present our instrumentation and method development during the past funding period towards this goal, and outline the proposed studies.
Another question concerns the formation and destruction of PAHs. We will study directly, by mass spectroscopic means, the dissociation processes of PAH ions irradiated by visible and UV light. Related to this, 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. First results on the linear C3H+ ion obtained with a newly developed scheme for rotational action spectroscopy will be shown [1].
[1] Brünken et al., ApJ 783 (2014) L4
Author
Dr
Sandra Brünken
(Universität zu Köln)