Dresden 2026 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 4: Metal & Semiconductor substrates: Adsorption and reaction of small molecules I

O 4.3: Vortrag

Montag, 9. März 2026, 11:00–11:15, HSZ/0401

Investigating CO Oxidation on Rh(111)/(332) with High-Repetition-Rate Velocity Resolved Kinetics — •Johannes Diedrich, Arved Dorst, and Tim Schäfer — Georg-August-Universität Göttingen, Institut für Physikalische Chemie, Tammannstr. 6, 37077 Göttingen

Velocity resolved kinetics (VRK) allows measuring the temporal evolution of reaction products from surfaces. A recent development is high repetition rate (HRR)-VRK [1]. By using more ionization pulses per molecular beam pulse, the signal-to-noise ratio is significantly improved and data acquisition accelerated.

An ultra-high-vacuum apparatus used for conventional VRK was modified to HRR-VRK by using a 100 kHz femtosecond laser for multiphoton nonresonant ionization and a TimePix3 event camera. This setup enables measururement of the full time of flight spectrum for every laser pulse.

Preliminary results are presented for the oxidation of CO on Rh(111) and (332) facets. This system allows comparison of conventional and HRR-VRK for a previously investigated reaction [2]. Thermal and hyperthermal CO2 channels are distinguished and deviations from the single-exponential decay are discussed. In future work, the decomposition of hydrazine on Ir will be investigated to gain a deeper understanding of Ir-based monopropellant thruster catalysts.

[1] F. Nitz et al., Rev. Sci. Instrum. 96, 055106 (2025).

[2] A. C. Dorst, PhD diss. (Georg-August-University Goettingen 2025).

Keywords: Velocity resolved kinetics; Ion imaging; CO oxidation; Rh; surface reaction