title: The submersion of sodium clusters in helium nanodroplets: identification of the surface → interior transition.
abstract: The submersion of sodium clusters beyond a critical size in helium nanodroplets, which has recently been predicted on theoretical grounds, is demonstrated for the first time. Confirmation of a clear transition from a surface location, which occurs for alkali atoms and small clusters, to full immersion for larger clusters, is provided by identifying the threshold electron energy required to initiate Na(n) cluster ionization. On the basis of these measurements, a lower limit for the cluster size required for submersion, n ≥ 21, has been determined. This finding is consistent with the recent theoretical prediction.
authors.affiliation: Institut für Ionenphysik und Angewandte Physik und Research Platform Advanced Materials, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
authors.forename: Lukas
authors.initials: L
authors.lastname: An der Lan
authors.forename: Peter
authors.initials: P
authors.lastname: Bartl
authors.forename: Christian
authors.initials: C
authors.lastname: Leidlmair
authors.forename: Harald
authors.initials: H
authors.lastname: Schöbel
authors.forename: Roland
authors.initials: R
authors.lastname: Jochum
authors.forename: Stephan
authors.initials: S
authors.lastname: Denifl
authors.forename: Tilmann D
authors.initials: TD
authors.lastname: Märk
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Ellis
authors.forename: Paul
authors.initials: P
authors.lastname: Scheier