Bonn 2025 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 20: Poster – Molecular Spectroscopy and Dynamics

MO 20.6: Poster

Mittwoch, 12. März 2025, 17:00–19:00, Tent

Detailed investigation of unexpected photoelectron spectra via angle-resolved spectroscopy of Gold clusters — •Steve Takouan Tchounga, Lucas Weise, and Bernd von Issendorff — Physikalisches Institut, Albert-Ludwigs-Universität, Freiburg im Breisgau, Germany

Angle-resolved spectroscopy provides an important test of the theoretical description of clusters since these spectra carry more information than the bare electron binding energies. Specifically,the anisotropy of photoelectron spectra depends on the angular momentum state [1]. In the experiment cluster anions are produced in a magnetron sputter source, cooled to 7K, and enter a time-of-flight spectrometer for mass selection. Electrons are then detached by linear polarised laser light and projected onto an MCP detector in a velocity map imaging setup.

The presented analysis utilizes the additional information from angle-resolved spectroscopy to gain a better understanding of the electronic structure of the cluster. For Au₃₃⁻ an electronic shell closing is expected, leading to the opening of a new shell for Au₃₄⁻. The angular momentum character of this new shell is not in accordance with a simple shell model. It also differs from the mixed character as observed for Sodium clusters of the same size [2]. Possible influences of the high-lying d-band are discussed.

[1] A. Piechaczek, C. Bartels, C. Hock, J.-M. Rost, and B. v. Issendorff, Phys. Rev. Lett. (2021), 126.

[2] C. Bartels, C. Hock, R. Kuhnen, M. Walter, and B. v. Issendorff, Phys. Rev. A (2013), 88.

Keywords: Gold clusters; Photoelectron; Angle-resolved spectroscopy; Mixed states; Cluster anions