Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 10: Focus Session: Single Atom Catalysis 2

O 10.3: Vortrag

Montag, 5. September 2022, 15:45–16:00, H4

A Customized IRAS System for Investigations of Adsorbates on Metal-Oxide Single Crystals — •David Rath, Jiri Pavelec, Ulrike Diebold, Michael Schmid, and Gareth S. Parkinson — Institute of Applied Physics, TU Wien, Austria

The IRAS system GRISU (GRazing incident Infrared absorption Spectroscopy Unit) was developed to investigate adsorbates on metal oxide single crystals in the research field of single-atom catalysis [1]. It combines the commercially available FTIR spectrometer Bruker Vertex 80v with an UHV chamber [2]. The compact design requires only one CF150 port for the main optical components, features five mirrors for beam guidance placed in HV and UHV environment and optimises the system’s performance, flexibility, and usability. The result is a small controllable focal-spot diameter (max. 3 mm) on the sample, motorised optical components, and an aperture limiting the incidence angle range (variable, 49^∘ to 85^∘) on the sample. The simulated system (done with a ray-tracing program and a simplified spectrometer model) shows an efficiency of 13 %, i.e., 13 % of the radiation passing through the first aperture (Ø 6 mm) after the IR source in the FTIR spectrometer reaches the detector after being reflected from the molecular beam spot (Ø 3.5 mm) on the sample. Compared to a commercially available system with two parabolic mirrors with a focal length of 250 mm, the efficiency is about 20× higher. First measurements demonstrate the performance of the system.

[1] G. S. Parkinson, Catal. Lett. 149, 1137 (2019)

[2] J. Pavelec, et al., J. Chem. Phys. 146, 014701 (2017).