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.

Characterization of neutral boron-silicon clusters using infrared spectroscopy: The case of Si6B

“…The two parallel laser beams from the backside of the source are deflected to hit each rod at an angle of 60° with respect to the channel axis. This design ensures good spatial overlap of the ablation plumes, which is crucial for stable and controllable formation of binary clusters [43]. A solenoid valve (General Valve Series 9) is used to provide short helium carrier gas pulses (several 100 µs) at a backing pressure of about 4 bar.…”

“…To produce mixed clusters, various approaches have been demonstrated, such as single targets of alloys [34], binary compounds [35][36][37], pressed mixed powders [38,39], and dual-target (dual-laser) sources [40][41][42][43][44]. The dual-target dual-laser source designs allow for controlling the mixing ratios by changing the laser fluences, laser timing, and the rotation and/or translation speeds of the targets.…”

Vibrational spectra and structures of neutral Si6X clusters (X = Be, B, C, N, O)

“…12,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34], only a few experiments have been reported in the gas phase. 8,14,[35][36][37][38] By sequential doping of silicon clusters with carbon atoms, i.e., for Si m C n with m + n = 6, we recently observed a systematic transition from one-dimensional geometries for pure C 6 to three-dimensional structures for pure Si 6 . 38 In this study, we present complementary experimental and theoretical results on silicon clusters doped with first row elements (Si 6 X, with X = Be, B, C, N, O).…”

Structural Identification of Caged Vanadium Doped Silicon Clusters

“…Although mass spectrometry and photodissociation experiments [8,[16][17][18][19] show an enhanced stability of specific transition-metal doped silicon clusters, no single experiment has yet provided detailed information on their structure. Up to now, mainly indirect evidence is found for the formation of symmetric species by photoelectron and x-ray spectroscopy studies [20][21][22] and chemical probe methods [20,23].…”