High-resolution photoelectron spectroscopy on cold metal clusters

Abstract: A new high-resolution type of magnetic bottle photoelectron spectrometer (MB-PES) has been tested at energies allowing for valence and shallow core electrons studies at the same time. The established laboratory setup with Doppler compensation and time-dependent electron deceleration was optimised to a resolution of ∆E/E = 0.21% respectively 5.5meV at 2.54eV kinetic energy. This is at least a factor of five better than a standard MB-PES and still competitive with an hemispherical electron energy analyser whose drawback is a significantly worse collection efficiency. Combining the improved spectrometer with a suitable picosecond laser operating at 211nm, a large extent of the narrowly spaced energy levels of gold clusters up to Au-44 has been investigated via photoelectron spectroscopy. Many vibration modes have been observed for small gold clusters and different isomers could be identified for larger cluster sizes. Measurements on tantalum clusters Ta-4 to Ta-30 have been performed. The tantalum clusters have also been measured with niobium cluster Nb-9 to Nb-30 at 157nm, showing an unprecedented range of their valence band.
For experiments at FLASH2, a new XUV MB-PES has been designed and tested at the beamline in order to address the core levels of metal clusters. The high photon energy of 47eV with decent bandwidth allows us to investigate the 5d levels of lead, including their spin-orbit-splitting, and the 4d band of silver clusters with a unique resolution and short measurement time. In this high-intensity regime, higher different charge states have been observed. The results provide a rather comprehensive characterization of the size-dependence of the valence and shallow core states density of lead cluster anions in the size range from Pb-3 to Pb-50 and Ag-8 to Ag-70. An earlier observation indicating a metal-to-nonmetal transition [1] has been disproved, since the evolution of the 5d energies shown here is consistent with the trend of the 4f levels [2]

Angaben zum Objekt

• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch
• Anmerkungen: Universität Freiburg, Dissertation, 2023

Klassifikation und Themen

• Schlagwort: Cluster ; Elektronenstruktur ; Photoelektronenspektroskopie ; Metallcluster ; Clusterphysik ; Photoelektronenspektrometer ; Photoelektronenspektroskopie ; Ultraviolett-Photoelektronenspektroskopie ; Gold ; Silber ; Tantal ; Niob ; Blei ; Platin ; Freie-Elektronen-Laser

Beteiligte, Orts- und Zeitangaben

• Ereignis: Veröffentlichung
• (wo): Freiburg
• (wer): Universität
• (wann): 2023
• Urheber: Bär, Fabian
• Beteiligte Personen und Organisationen: Issendorff, Bernd von ; Issendorff, Bernd von ; Schätz, Tobias ; Albert-Ludwigs-Universität Freiburg. Physikalisches Institut ; Albert-Ludwigs-Universität Freiburg. Fakultät für Mathematik und Physik

Weitere Informationen

• DOI: 10.6094/UNIFR/237632
• URN: urn:nbn:de:bsz:25-freidok-2376320
• Rechteinformation: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Letzte Aktualisierung: 25.03.2025, 13:51 MEZ