The UV-absorption of europium atoms embedded in helium nanodroplets

• DOI: 10.1007/s004600050101
• Publication Date: 2002-08-25T08:52:48Z
• Authors: F. Federmann; A. Bartelt; J. D. Close; K. Hoffmann; N. Quaas; J. P. Toennies
• Keywords: Europium; Helium gas

We have measured the UV-absorption spectrum (4f→5d transitions) of single europium atoms embedded in helium droplets using a beam depletion technique. The electronic levels involved in the transition lie spatially within the closed 6s2 shell leading to significant shielding from the surrounding helium environment. We observe the narrowest absorption lines ever reported in liquid helium and compare our data and experimental method, with experiments carried out in bulk liquid helium.