Rostock 2019 – scientific programme

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MO: Fachverband Molekülphysik

MO 22: Posters 3: Cluster, Strong Field Physics, and Experimental Techniques

MO 22.7: Poster

Thursday, March 14, 2019, 16:15–18:15, S Foyer LLM

Ultra-high resolution photoelectron spectroscopy on deeply cold niobium clusters — •Fabian Bär, Moritz Weigt, and Bernd v. Issendorff — Physikalisches Institut Albert-Ludwigs Universität Freiburg

The properties of deeply cold niobium clusters Nb₄⁻ to Nb₃₅⁻ at 3.9 K have been investigated. Therefore, preparatory measurements with platinum ions have been performed, showing that the used magnetic bottle time of flight photoelectron spectrometer has a current resolution of Δ E/E = 0.39%. This is at least a factor five better than a standard magnetic bottle spectrometer. Striking vibration structures in several photoelectron spectra at cluster temperatures from 3.9 K to 122 K have been found, but so far no evidence for a phase transition involving a superconducting state has been observed. Using an improved setup with a low temperature ion trap and a new spectrometer, vibrational structures of different cluster sizes have been resolved and analysed. In the spectrum of Nb₂₆⁻ an unexpectedly vibrational transitions have been observed, indicating a cluster geometry with high symmetry. Additionally, the electron affinity of these clusters has been determined at a higher precision.