Unveiling Interstellar Chemistry in the Laboratory: Experimental Methods Development and Challenges. – (Myriam DRISSI / LCAR / Seminar). – 19/11/2026, 11H

Séminaire LCAR

Myriam Drissi, Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck 6020, Austria

Abstract
Understanding the diversity of molecules detected in the interstellar medium (ISM) requires detailed knowledge of the chemical and physical processes that occur under interstellar conditions. Laboratory astrophysics provides a means of investigating these processes under controlled conditions and generating the experimental data needed to constrain astrochemical models. However, obtaining such data can be challenging, as many species of astrophysical interest are highly reactive and short-lived. These include ions and radicals, which often need to be generated in situ and are therefore available only in small quantities. In addition, isolating individual processes and reproducing the low-temperature conditions characteristic of the ISM impose further experimental constraints. These experimental challenges have driven the development of detection techniques that combine high sensitivity, selectivity, and multiplexing capabilities. Such advances are essential for obtaining reliable molecular data and, ultimately, improving our understanding of the chemistry that governs the ISM. In this seminar, I will present recently developed experimental techniques for investigating neutral– neutral processes, including chemical reactions and nucleation. Particular emphasis will be placed on the CRESU technique (Cinétique de Réaction en Écoulement Supersonique Uniforme), which enables kinetic studies at low temperatures, and on fast-flow tube reactors, both of which provide controlled environments for studying these processes. I will also discuss complementary detection methods used to characterise the species involved and the processes under investigation, including microwave spectroscopy and double-imaging photoelectron photoion coincidence spectroscopy (i2PEPICO) coupled with synchrotron radiation. Through representative applications, I will highlight the capabilities and limitations of each approach. I will also discuss the developments made to overcome experimental challenges, particularly targeting the detection limit.