Mainz 2017 – scientific programme
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MO: Fachverband Molekülphysik
MO 7: Helium Droplets and Systems (with A)
MO 7.4: Talk
Tuesday, March 7, 2017, 15:30–15:45, N 6
Gold doped helium nanodroplets: Electronic spectroscopy from atoms to nanoparticles — •Florian Lackner, Maximilian Lasserus, Roman Messner, Martin Schnedlitz, Alexander Volk, Philipp Thaler, and Wolfgang E. Ernst — Institute of Experimental Physics, TU Graz
The isolation of nanoparticles in helium nanodroplets offers low temperature confinement for a dopand size regime ranging from single atoms and molecules to large clusters and elongated wire-structures. Excitation spectra of gold atoms, residing inside the droplets, appear strongly blue shifted due to the repulsive Pauli interaction of excited electrons with the He environment. Consequently, for the 5d106p 2P1/2o ← 5d106s 2S1/2 transition in Au-HeN we observe a broad structure extending more than 800 cm−1 to the blue of the bare atom line located at 37,359 cm−1. This feature is superimposed by a peak around 37,950 cm−1 attributed to atoms that have relaxed into the 5d96s2 2D manifold, a pathway enabled by the droplet environment and forbidden in the free atom. Absorption spectra of larger nanoparticles can be recorded ex-situ after deposition on fused silica substrates. First results on Au nanoparticles prepared by helium nanodroplets show a characteristic surface plasmon resonance peaking around 530 nm. We expect that the formidable doping capabilities provided by helium nanodroplets will allow for the study of the electronic structure of a large variety of mono- and bi-metallic nanoparticles ranging from single atoms and molecules to large nanoparticles.