title: Electronic and geometric stabilities of clusters with transition metal encapsulated by silicon.
abstract: Silicon clusters mixed with a transition metal atom, MSin, were generated by a double-laser vaporization method, and the electronic and geometric stabilities for the resulting clusters with transition metal encapsulated by silicon were examined experimentally. By means of a systematic doping with transition metal atoms of groups 3, 4, and 5 (M = Sc, Y, Lu, Ti, Zr, Hf, V, Nb, and Ta), followed by changes of charge states, we explored the use of an electronic closing of a silicon caged cluster and variations in its cavity size to facilitate metal-atom encapsulation. Results obtained by mass spectrometry, anion photoelectron spectroscopy, and adsorption reactivity toward H2O show that the neutral cluster doped with a group 4 atom features an electronic and a geometric closing at n = 16. The MSi(16) cluster with a group 4 atom undergoes an electronic change in (i) the number of valence electrons when the metal atom is substituted by the neighboring metals with a group 3 or 5 atom and in (ii) atomic radii with the substitution of the same group elements of Zr and Hf. The reactivity of a halogen atom with the MSi(16) clusters reveals that VSi(16)F forms a superatom complex with ionic bonding.
authors.affiliation: Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama 223-8522, Japan.
authors.forename: Kiichirou
authors.initials: K
authors.lastname: Koyasu
authors.forename: Junko
authors.initials: J
authors.lastname: Atobe
authors.forename: Minoru
authors.initials: M
authors.lastname: Akutsu
authors.forename: Masaaki
authors.initials: M
authors.lastname: Mitsui
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nakajima