During his PhD studies, Steffen Friis Holleufer developed tunable silicate thin films for applications in experimental astrochemistry. Silicate dust grains in the interstellar medium are expected to act as catalysts in the formation of organic molecules under interstellar conditions, driving the evolution of chemical complexity. Steffen Friis Holleufer prepared silicate thin films, which can act as interstellar silicate model systems. The thin films can be grown and characterised in ultra-high vacuum laboratory environments, allowing astrochemically-relevant investigations of silicate surface chemistry under controlled conditions. The chemical composition of the synthesised films can also be tuned, making it possible to account for variations in dust stoichiometries.

Future experimental application of the interstellar silicate model systems will contribute to the understanding of the role of interstellar silicate dust grains as drivers of the chemical complexity in the interstellar medium.
The PhD study was completed at Interdisciplinary Nanoscience Center (iNANO), Faculty of Natural Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Thursday, 12 February 2026 at 13:15
Place: Building 1525, room 626, Det Skæve Rum, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C
Title of PhD thesis: Synthesis of tunable interstellar silicate model systems for experimental surface astrochemistry
Contact information: Steffen Friis Holleufer, e-mail: sfholleufer@phys.au.dk, tel.: +45 30 12 88 35
Members of the assessment committee:
Senior lecturer Jan Knudsen, Synchrotron Radiation Research, Lund University and MAX IV, Sweden
Professor Barbara Lechner, Department of Chemistry, Technical University of Munich, Germany
Professor Mingdong Dong (chair), Interdisciplinary Nanoscience Center, Aarhus University, Denmark
Main supervisor:
Professor Liv Haahr Hornekær, Department of Physics and Astronomy, Aarhus University, Denmark
Co-supervisors:
Professor Jeppe Vang Lauritsen, Interdisciplinary Nanoscience Center, Aarhus University, Denmark
Andrew Cassidy, Department of Physics and Astronomy, Aarhus University, Denmark
Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Natural Sciences/GSNS, Ny Munkegade 120, building 1521, 8000 Aarhus C