Freiburg 2024 – scientific programme

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MO: Fachverband Molekülphysik

MO 18: Poster: Cluster

MO 18.3: Poster

Wednesday, March 13, 2024, 17:00–19:00, Tent C

Detailed investigation of unexpected photoelectron spectra via angle-resolved spectroscopy of Gold clusters — •Steve Takouan Tchounga, Lukas Weise, and Bernd von Issendorff — Physikalisches Institut der Albert-Ludwigs-Universität Freiburg, 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. 126, 233201 (2021). [2] C. Bartels, C. Hock, R. Kuhnen, M. Walter, and B. v. Issendorff, Physical Review A 88, 043202 (2013).

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