Super‐atom properties of 13 atom clusters of group 13 elements

Abstract

We report first principles calculations of the geometry and electronic structure of 13 atom clusters of boron, aluminium, gallium and indium. These density functional theory calculations support the jellium model in the energy levels and molecular orbitals of the cluster and enable us to discuss the relevance of the superatom concept. We go on to examine a number of cluster symmetries in detail as a function of charge and comment on the successes and limitations of the jellium and superatom models in describing these clusters. In particular we find that the monovalent anionic cluster is the most stable and has the most symmetric structure. As charge changes the symmetry of the clusters decreases in a way that is dependent on symmetry and charge, but not atomic species.

Superatomic Gallium Clusters in Dendrimers: Unique Rigidity and Reactivity Depending on their Atomicity

“…Therefore, the obtained clusters are strongly affected by their thermodynamic stability. [28] In this study, we demonstrate control of the valence electrons in superatomic gallium clusters [26,27,29,30] using our superatom synthesizer, that is, fourth generation dendritic polyphenylazomethines (DPAs). [31] Gallium is known to have a low melting point compared to other metals in the bulk state.…”

“…The feature is considered to be derived from both of the closed shell electronic structure and geometrically stable conformation. [12,13,26,29,30] The solution-phase synthesis of gallium clusters enabled evaluation of the oxidation potentials by electrochemical measurements. A differential pulse voltammetry (DPV) curve of the fabricated [Ga] 13 sample is shown in Figure 3.…”

“…Therefore, the observed rigid form of the 13‐atom gallium cluster suggests its thermodynamic high stability compared to other forms with low symmetry. The feature is considered to be derived from both of the closed shell electronic structure and geometrically stable conformation 12,13,26,29,30…”

Magnetic Properties and the Superatom Character of 13-Atom Platinum Nanoclusters

“…For the superatom the situation is quite analogous to that of the transition metal ion. In the simple jellium model, the 5d 9 6s 1 valence electrons of atomic Pt occupy superatom states with s, p, d, f, g, and h character, corresponding to cluster molecular orbitals with angular momenta ℓ = 0, 1, 2, 3, 4, and 5 [32,33]. More adequate DFT calculations for an icosahedral Pt13 cluster yield the energy levels shown in Figure 2 (left) [34].…”

“…It affects the energies of Pt cluster orbitals by up to 2.5 eV while the effect of Jahn-Teller distortions is smaller by two orders of magnitude [34]. Furthermore, the impact by the environment in the zeolite pores, such as the charge balancing protons and alkali ions, influences the energy levels and may break any residual symmetry and disturb significantly the clear shell structure of the symmetric species [32]. This leads to a varying energetic structure with a density of 6-8 states per 1 eV around the Fermi energy of Pt13 clusters [33,34].…”