Geometric and electronic structures of terbium-silicon mixed clusters (TbSi_n; 6 ≤ n ≤ 16)

The geometric and the electronic structures of terbium-silicon anions, TbSi_n ^- (6 ≤ n ≤ 16) were investigated by using photoelectron spectroscopy (PES) and a chemical-probe method. The clusters were produced by a double-rod laser vaporization technique. From trends observed in the electron affinities (EAs), the TbSi_n ^- clusters were categorized into three groups of (I) 6 ≤ n ≤ 9, (II) n = 10, 11, and (III) n ≥ 12. Together with adsorption reactivity toward H₂O it is concluded that a Tb atom is encapsulated inside a Si_n cage at n ≥ 10; Tb@Si_n.