Erlangen 2022 – scientific programme

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MO: Fachverband Molekülphysik

MO 8: Poster 1

MO 8.11: Poster

Tuesday, March 15, 2022, 16:30–18:30, P

Infrared Action Spectroscopy of Single Nanoparticles in the Gas Phase — •Sophia Leippe, Benjamin Hoffmann, and Knut R. Asmis — Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, 04103 Leipzig, Germany

The surface of a nanoparticle (NP) can be characterized by infrared spectroscopy in the gas phase in order to avoid perturbing interactions with its environment. Since direct absorption spectroscopy is typically not sensitive enough for this purpose, alternative methods are required, in which the absorption of photons is detected indirectly by way of action spectroscopy. A novel single NP mass spectrometer is used that allows to non-destructively monitor the absolute mass of the NP. Adsorption of messenger compounds onto the NP is enabled by a temperature-controllable (10 - 350 K) ion trap. Absorption of electromagnetic radiation leads to heating of the NP and evaporation of the messenger, which is indirectly detected as a loss of mass. Proof-of-principle experiments showed that UV/VIS action spectra are in reasonable agreement with direct absorption spectra obtained from measurements in solution.[1] We are currently extending this technique to the infrared regime (4200 - 2500 cm-1) and first results are reported here. Single NP infrared action spectroscopy can ultimately provide new insights which are of interest for various fields, such as catalysis, material separation or medicine.

[1] B. Hoffmann, T. K. Esser, B. Abel, K. R. Asmis, J. Phys. Chem. Lett. 11, 6051*6056 (2020)