title: Chemical characterization of an alkali-like superatom consisting of a Ta-encapsulating Si16 cage.
abstract: Chemical characterization was performed for an alkali-like superatom consisting of a Ta-encapsulating Si16 cage, Ta@Si16, deposited on a graphite substrate using X-ray photoelectron spectroscopy (XPS) to element-specifically clarify the local electronic structure of the cage atoms. The XPS spectra derived from Ta 4f and Si 2p core levels have been well modeled with a single chemical component, revealing the formation of a symmetric Si cage around the Ta atom in the deposited nanoclusters. On chemical treatments by heating or oxygen exposure, it is found that the deposited Ta@Si16 is thermally stable up to 700 K and is also exceptionally less reactive toward oxygen compared to other Ta-Si nanoclusters, although some heat degradation and oxidation accompany the treatments. These results show the promising possibility of applying Ta@Si16 as a building block to fabricate cluster-assembled materials consisting of naked nanoclusters.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shibuta
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ohta
authors.affiliation: Nakajima Designer Nanocluster Assembly Project, JST-ERATO , 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Nakaya
authors.affiliation: Nakajima Designer Nanocluster Assembly Project, JST-ERATO , 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012, Japan.
authors.forename: Hironori
authors.initials: H
authors.lastname: Tsunoyama
authors.affiliation: Nakajima Designer Nanocluster Assembly Project, JST-ERATO , 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012, Japan.
authors.forename: Toyoaki
authors.initials: T
authors.lastname: Eguchi
authors.affiliation: Nakajima Designer Nanocluster Assembly Project, JST-ERATO , 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nakajima