The lowest-energy structures and low-lying isomers of double impurity atoms, Ga and Mn, doped Lin (n = 1–12) clusters have been systematically investigated using density functional theory. The trimetallic clusters show larger relative binding energies compared with the bare Lin+2 partners, indicating doping with Ga and Mn atoms could enhance the stabilities of Lin clusters. The HOMO–LUMO gaps, the vertical ionization potentials and the vertical electron affinities have also been analyzed and compared with the pure lithium clusters. The magnetism calculations demonstrate that the magnetic moments of GaMnLin clusters show a tunable magnetic properties with the increasing number of Li atoms.

The energetic and electronic properties of acetylenic-bond-interconnected hexagonal boron nitride sheets (BNyne), in which the number of rows of BN hexagonal rings (denoted as BN width) between neighboring arrays of acetylenic linkages increases consecutively, have been explored using first-principles calculations. Depending on the spatial position of B/N atoms with respect to the acetylenic linkages, there are two different types of configurations. The band structure features and band gap evolutions of BNyne structures as a function of the BN width can be categorized into two families, corresponding to two distinct types of configurations. In particular, for both types of BNyne structures, the band gap variations exhibit odd–even oscillating behavior depending on the BN width, which is related to the different symmetries of acetylenic chains in the unit cell. These results suggest that the embedded linear acetylenic chains can provide more flexibility for manipulation of the atomic and electronic properties of hexagonal boron nitride. These sp–sp2 hybrid structures might promise importantly potential applications for developing nanoscale electronic and optoelectronic devices.

New low-energy atomic structures and properties of medium-size gold nanoparticles (Au33–42) are studied, where the atomic positions of gold atoms are obtained on the basis of the generic formulation of shell and core concept. Hollow cage, tube-like, double-layered flat, fcc-like, and close-packed configurations are predicted. Relativistic density functional theory optimization indicated that low-symmetry stuffed configurations are all lower in energy than the others. Further analysis of the optimized structures of Au33–42 nanoparticles shows that these gold cores are all four-atom tetrahedral structures and similar to each other; only the number and positions of gold atoms at the surface of gold core are different. Compared with structure and electronic properties, Au33–42 nanoparticles have different structure stabilities and chemical activities. But they are all hybridizations of sp and d electrons. The obtained information forms the basis for future chemisorption studies to unravel the catalytic effects of gold nanoparticles.

Chirality, also called handedness, plays a crucial role in function ranging from biological self-assembly schemes, organic polymer functionalities, to optical material designs. In this Article, we demonstrated a first-principles investigation of chirality in magnetic AlMnAun0/+1/–1 (n = 1–7) clusters. Optimized structures of the AlMnAun clusters exhibit configurational combinations between AlAun+1 and MnAun+1 clusters, indicating a subtle but equal competition between Au–Al and Au–Mn interactions in the alloy clusters. High magnetic moments are equal to or greater than 4μB in AlMnAun clusters due to the presence of the Mn dopant. Chirality turns up with the forms of right-handed and left-handed in stable AlMnAu5, AlMnAu6, and AlMnAu7 clusters. As a result, reflection symmetries are found in vibrational Raman and circular dichroism spectra of these chiral pairs. The present study shows that chiral magnetic clusters can be composed by doping two heteroatoms with one intrinsic magnetic dopant into small gold clusters.

We demonstrated a first-principles investigation to search for magnetic superatoms in the vanadium-doped lithium clusters VLin (n = 1–13). The stabilities of VLin clusters were determined through geometrical and electronic optimizations. It is found that the growth pattern of VLin in 3-space follows adding a Li atom capped on VLin–1 clusters. All doped clusters show larger relative binding energies compared with pure Lin+1 partners and display tunable magnetic properties. When n = 8–13, the VLin clusters adopt a cage-like structure with an endohedral V atom and are identified as superatoms with their magnetic moments successively decreasing from 5 to 0 μB. The isolated VLi8 superatom is emphasized due to its robust magnetic moment as well as high structural and chemical stability analogue of a single Mn2+ ion. Molecular orbitals analysis shows that VLi8 has an electronic configuration of 1S21P61D5, exhibiting Hund’s filling rule of maximizing the spin-like atoms. Electronic shell structures of 1S2 and 1P6 are virtually unchanged in Li9 cluster as the V atom substitutes for the embedded Li atom, indicating that the electron-shell-closing model is valid for explaining its structures and stabilities. The results show that the tailored magnetic building blocks for nanomaterials can be formed by seeding magnetic dopants into alkali metal cluster cages.

Taking Au38 as a prototype, hollow cages with different arrangements and those stuffed by a different number of atoms have been studied by using the scalar relativistic density functional theory. The global minimum structures of Au38i (i = 0, ±1) are found to exhibit low symmetry core-shell structures: Au38 and Au38− feature a four-atom tetrahedral core and Au38+ possesses a six-atom octahedron core. For the neutral Au38, the tube-like structure has the highest chemical stability. The obtained information forms the basis for future chemisorption studies to unravel the catalytic effects of gold nanoparticles.

First-principles calculations are carried out to investigate the hydrogen separation characteristics of two-dimensional carbon allotropes consisting of sp- and sp2-hybridized carbon atoms, i.e., graphyne, graphdiyne, and rhombic-graphyne. The selectivities for H2 over several gas molecules, including CO, N2, and CH4, are found to be sensitive to the pore sizes and shapes. The penetration barriers generally decrease exponentially with the pore sizes. Our results reveal that graphyne with small pores is unsuitable for the purpose of hydrogen separation. Graphdiyne, with larger pores, exhibits a high selectivity (109) for hydrogen over large gas molecules such as CH4, but a relatively low selectivity (103) over small molecules such as CO and N2. The large differences in diffusion barriers for molecules penetration through a rhombic-graphyne monolayer, which possesses pore size in between that of graphyne and graphdiyne, lead to a high selectivity (>1016) for hydrogen separation from the others. The results suggest that the abundant pores of different sizes in these carbon allotropes make them ideal molecular sieves for gas separation applications directed toward different separation needs and objectives.

The size-dependent electronic, structural, and magnetic properties of Mn-doped gold clusters have been systematically investigated by using relativistic all-electron density functional theory with generalized gradient approximation. A number of new isomers are obtained for neutral MnAun (n = 1–16) clusters to probe the structural evolution. The two-dimensional (2D) to three-dimensional (3D) transition occurs in the size range n = 7–10 with manifest structure competitions. From size n = 13 to n = 16, the MnAun prefers a gold cage structure with Mn atom locating at the center. The relative stabilities of the ground-state MnAun clusters show a pronounced odd–even oscillation with the number of Au atoms. The magnetic moments of MnAun clusters vary from 3 μB to 6 μB with the different cluster size, suggesting that nonmagnetic Aun clusters can serve as a flexible host to tailor the dopant’s magnetism, which has potential applications in new nanomaterials with tunable magnetic properties.

In the frame of density functional theory, the lowest energy structures of Au32−nAgn (n = 1–31) clusters are discussed by considering the hollow cage-like and space-filling structures. The calculated results show that the hollow cage-like and space-filling structures are competitive in energy. For Au32−nAgn clusters with sizes n = 1, 2, 5–8, 11, 12, 16, and 18, the hollow cage-like structures are their lowest energy structures. And for the clusters with other sizes, the space-filling structures are the corresponding lowest energy structures. In addition, the Au31Ag cluster with the hollow cage-like configuration is found to be highly stable in structure, and even more stable than the icosahedral Au32 cluster. It believes that the experimentalists are interested in the finding above.Graphical abstractAu31Ag cluster with the hollow cage-like configuration is found to be highly stable in structure, and even more stable than the icosahedral Au32 cluster.Highlights► Au32-nAgn(n=1–31)Au32-nAgn(n=1–31) clusters are discussed. ► Structures of Au32-nAgn(n=1,2,5–8,11,12,16,18) are hollow cage-like. ► Au31Au31Ag is found to be highly stable in structure, and even more stable than Au32Au32.

The lowest-energy structures and low-lying isomers of Pbn (n = 13–18) clusters are obtained by using MP2 method. In the considered configuration and size range, it is found that the lowest-energy structures of Pbn clusters favor compact structures, which is different from the prolate structures of Snn clusters at the same size range. For the lowest-energy structures, our calculated dipole moments indicate that the Pb14 and Pb18 clusters possess large dipole moments, which are in good agreement with available experiment.

The geometries, electronic, and magnetic properties of the Au7Hn (n = 1–10) clusters have been systematically investigated by using relativistic all-electron density functional theory with generalized gradient approximation. It is found that the Au7 on the whole retains its triangle structure after hydrogen atoms adsorption and adsorbing hydrogen atoms can stabilize the Au7 structure. The Au7H7 cluster is much higher stability than the neighboring clusters. The pronounced even–odd alternation of the magnetic moments is observed in the Au7Hn systems indicating Au7Hn clusters possess tunable magnetic properties by adding even or odd number of H atoms.

The energetic and electronic properties of acetylenic-bond-interconnected hexagonal boron nitride sheets (BNyne), in which the number of rows of BN hexagonal rings (denoted as BN width) between neighboring arrays of acetylenic linkages increases consecutively, have been explored using first-principles calculations. Depending on the spatial position of B/N atoms with respect to the acetylenic linkages, there are two different types of configurations. The band structure features and band gap evolutions of BNyne structures as a function of the BN width can be categorized into two families, corresponding to two distinct types of configurations. In particular, for both types of BNyne structures, the band gap variations exhibit odd–even oscillating behavior depending on the BN width, which is related to the different symmetries of acetylenic chains in the unit cell. These results suggest that the embedded linear acetylenic chains can provide more flexibility for manipulation of the atomic and electronic properties of hexagonal boron nitride. These sp–sp2 hybrid structures might promise importantly potential applications for developing nanoscale electronic and optoelectronic devices.