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O: Fachverband Oberflächenphysik
O 124: Development of Novel Methods II
O 124.2: Vortrag
Freitag, 20. März 2020, 10:45–11:00, WIL C107
Cryogenic Single Nanoparticle Action Spectroscopy (cryo-SNAS) - A New Tool for Surface Science of Single Nanoparticles — •Tim Esser1, Benjamin Hoffmann2, and Knut Asmis2 — 1University of Oxford, Oxford, UK — 2Universität Leipzig, Leipzig
Nanoparticles (NPs) with diameters from 10 to 100 nm have unique size and shape dependent properties due to their large surface-to-volume ratio and quantum effects. They are relevant in atmospheric and astro chemistry and applied in catalysis, energy storage, opto-electronics and bio-medicine. Their fundamental properties can be obscured in experiments that rely on averaging and interaction with surfaces or solutions. Action spectroscopy is a sensitive alternative to direct absorption spectroscopy for gas phase clusters and macroscopic surfaces, but was not previously applied to NPs due to limited sensitivity and resolution of most mass spectrometers above 1 MDa. Here we present a nanoparticle mass spectrometer which enables cryogenic single nanoparticle action spectroscopy (cryo-SNAS) for the first time. NPs from an electrospray ion source are trapped in a temperature controllable (8 to 350 K) split-ring electrode ion-trap. The mass-to-charge ratio and absolute mass of a single NP is determined non-destructively by optical means. Mass variations can then be monitored as a function of the trap temperature, pressure, laser power and wavelength.
First cryo-SNAS spectra of dye labeled SiO2 NPs are shown followed by a discussion of future applications.