INSP - UPMC - 4 place Jussieu - 75005 Paris - Barre 22-12, 4e étage, salle 426
Minna Patanen - Université d’Oulu, Finlande
Abstract
Soft X-ray photoelectron spectroscopy of freestanding nanoparticles and clusters is a highly surface sensitive method, allowing studies of unique properties of these nanosystems to be performed in absence of an interaction with a substrate and charging effects. The pioneering works by Mysak et al. [1] and Wilson et al. [2] have paved the way for the rapidly growing field of nanoparticle electron spectroscopy with emerging applications for example in aerosol science, surface catalysis and photovoltaics. On the other hand, gas-phase cluster studies have a much longer tradition, the first synchrotron radiation excited core level photoelectron experiments dating back to the mid-1990’s [3,4]. Third generation synchrotron radiation facilities have enabled studies of more and more dilute samples. New instrumentation, like fast-readout position sensitive detectors and wide acceptance angle hemispherical electron analysers, make it possible to obtain reasonable resolution with high count rates. I will introduce some recent soft X-ray spectroscopy studies of very dilute clusters species, carried out at PLEIADES beamline at Synchrotron SOLEIL (Saint-Aubin, France) and I411 beamline at MAX IV facility (Lund, Sweden). Advances in light sources, beamlines, and analysers have opened a way to perform systematic studies requiring stable experimental conditions over a long period of time. Such kind of experiment is needed for example to study the surface vs. bulk structure of free-standing clusters [5], evolution of crystal structure and solvation of small salt clusters [6], or surface segregation of salt nanoparticles [7]. As an outlook to the future, the prospects of synchrotron radiation excited soft X-ray spectroscopy of nanoparticles will be discussed, especially the possibilities to benefit from spectromicroscopy.
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[5] Patanen M, Benkoula S, Nicolas C, Goel A, Antonsson E, Neville J J, Miron C, J. Chem. Phys. 143, 124306 (2015).
[6] Hautala L, Jänkälä K, Mikkelä M-H, Turunen R, Prisle N, Patanen M, Tchaplyguine M, Huttula M, Phys. Chem. Chem. Phys. 19, 25158 (2017).
[7] Antonsson E, Patanen M, Nicolas C, Benkoula S, Goel A, Neville J J, Miron C, Phys. Rev. X 5, 011025 (2015).