Regensburg 2025 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 72: Poster Plasmonics and Nanooptics: Light-Matter Interaction, Spectroscopy
O 72.13: Poster
Mittwoch, 19. März 2025, 18:00–20:00, P2
Kinetics of hydrogen molecules on Ag(111) by tip-enhanced Raman spectroscopy — Shuyi Liu1,2, Jun Yoshinobu3, Martin Wolf1, Takashi Kumagai4, and •Akitoshi Shiotari1 — 1Fritz-Haber Institute of the Max-Planck Society, Berlin, Germany — 2Huazhong University of Science and Technology, Wuhan, China — 3University of Tokyo, Kashiwa, Japan — 4Institute for Molecular Science, Okazaki, Japan
Surface diffusion is the first step for adsorbates to undergo characteristic chemical and physical phenomena such as self-assembly, catalytic reactions, and low-dimensional molecular transport. However, the characterization of highly diffusive molecules, such as physisorbed molecules, has been challenging even with scanning tunneling microscopy and its related techniques. In this study, we use tip-enhanced Raman spectroscopy (TERS) to sensitively detect hydrogen molecules physisorbed on Ag(111) at low temperatures around 10 K. Strong Raman peaks were observed only when the diffusive molecule entered the plasmonic tip-sample junction, while the peaks decayed by thermal desorption at higher temperatures. By monitoring the peak intensities and investigating its temperature dependence, we successfully analyzed the kinetics of hydrogen molecules on the surface. This demonstrates that TERS is useful for evaluating the dynamics of diffusive molecules.
Keywords: Tip-enhanced Raman spectroscopy; Scanning tunneling microscopy; Plasmonic picocavity; Hydrogen; Surface diffusion