Growth Mechanism and Chemical Bonding in Scandium‐Doped Copper Clusters: Experimental and Theoretical Study in Concert

Abstract

Size matters! The electronic structure and size-dependent stability of neutral and cationic scandium-doped copper clusters have been investigated by mass spectrometric studies (for the cations) and also quantum chemical computations. The proposed reaction paths ultimately lead to the most stable Frank-Kasper-shaped Cu(16)Sc(+) cluster (shown here), which could be the germ of a new crystallization process.Electronic structure and size-dependent stability of scandium-doped copper cluster cations, Cu(n)Sc(+), were investigated by using a dual-target dual-laser vaporization production scheme followed by mass spectrometric studies and also quantum chemical computations in the density functional theory framework. The neutral species also were studied by using computational methods. Enhanced abundances and dissociation energies were measured in the case of Cu(n)Sc(+) for n=4, 6, 8, 10 and 16, the last of these identified as being extraordinary stable. Neutral clusters are stable with n=5, 7, 9 and 15, which are isoelectronic with respect to the number of the valence s electrons with the stable cationic clusters; hence a simple electron count determines cluster properties to a great extent. The Cu(17)Sc cluster was found to be a superatomic molecule, containing Cu(16)Sc(+) and Cu(-) units; however, the charge separation is not as pronounced as in the case of CuLi. Cu(15)Sc was found to be a stable cluster with a large dissociation energy and a closed electronic structure; hence this can be regarded as a superatom, analogous to the noble gases. The main factors determining the growth patterns of these clusters are the central position of the scandium atom and the successive filling of the shell orbitals. For smaller clusters, the reaction paths appear to diverge yielding various products; however all paths ultimately lead to the most stable Frank-Kasper shaped Cu(16)Sc cluster, which in turn can be the germ of the crystallization process.

Screening of transition metal doped copper clusters for CO2 activation

“…The obtained lowest energy structures for Cu 3 Sc and Cu 3 V are consistent with previous results. 93,94 All lowest energy Cu 3 X clusters have planar rhombus shapes. The frontier orbitals of the Cu 3 X clusters are consistent with the phenomenological shell model (PSM) 95,96 as each copper atom contributes 1 valence electron, while the transition metal dopants contribute 2 to 4 itinerant electrons, resulting in 1s 2 p 2-5 electronic structures.…”

Impurity Electron Localization in Early-Transition-Metal-Doped Gold Clusters

“…So far, the amount of electron localization in doped clusters could only be probed indirectly, e.g., in photofragmentation studies combined with a phenomenological shell model [11][12][13][14][15][16][17] or by valence band photoelectron spectroscopy which probes the total density of states. [18][19][20] Here, we apply the local and element specific method of x-ray absorption spectroscopy in combination with Hartree-Fock and charge transfer multiplet calculations to transitionmetal-doped gold clusters in order to unambiguously determine the amount of 3d-electron localization.…”

Exploration of the Structural, Electronic and Tunable Magnetic Properties of Cu4M (M = Sc-Ni) Clusters

“…Experimental and theoretical research has manifested that the introduction of a dopant atom into a small cluster can considerably change the nature of the host cluster. Copper clusters doped with an impurity atom have been actively pursued to tailor the desired structural, electronic, magnetic and optical properties for potential applications in solid state chemistry, materials science, nanotechnology and microelectronics [ 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ]. For example, the bimetallic Cu n Pd m ( ) clusters are more stable than the monometallic particles with the same size [ 35 ].…”

“…The bond stiffness of the copper cluster are decreased after doping with Pd atoms. The most stable Cu 7 Sc, Cu 15 Sc and Cu 16 Sc clusters could be regarded as a σ-aromatic species, a superatom and the germ of a crystallization process, respectively [ 37 , 38 , 39 ]. The Ti- and V-doping dramatically improves the adsorption of copper clusters on NO molecules, but it does not affect the O 2 adsorption probability significantly [ 40 ].…”