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Geometries and properties of (GaP)n (n = 1–38) nanocages are systematically investigated at the B3PW91 level. Particularly, the inner spaces, HOMO–LUMO gaps, and charge-transfers of the stable (GaP)n are generally increased as the sizes of (GaP)n being extended. The (GaP)n geometries undergo a structural variation with the size of clusters being increased. The medium size clusters present the hollow globular forms with large surface effect, based upon the calculated fragmentation energies and averaged atomic binding energies. The relative stabilities of (GaP)n nanoclusters are discussed. The stable (GaP)6 and (GaP)12 clusters are predicted, which can self-assemble 2D bilayer GaP nanosheets with possible stronger quantum efficiencies for optoelectronic devices or energy nanomaterials. The calculated energy gaps of (GaP)n show they are obviously width energy gap nanoclusters and have size dependent absorption wavelengths. The ionic bonds in (GaP)n are discussed and dominate gradually chemical bonding as the size of (GaP)n being increased, indicating that large-sized (GaP)n prefer to capture CO2 molecules and have properties of ionic semiconductors. [ABSTRACT FROM AUTHOR]

Growth-pattern behaviors, relative stabilities, geometrical and electronic properties of nanosize Pt 2 Si n (n = 10–20) semiconductor material are investigated by using density functional methods. Optimized geometries exhibit that transition metal Pt 2 is doped on small-size opened cage-like silicon frame with n = 10–15 while Pt 2 is encapsulated into close cage-like Si frame with n = 16–20; Based upon the calculated relative stabilities, the particular stable Pt 2 Si 16 unit is discovered. Furthermore, the dominant growth patterns of Pt 2 Si n (n = 10–20) are based upon the stable pentagonal prism PtSi 10 unit. Interestingly, the critical size of geometry transition with bimetal atoms being completely encapsulated into silicon frame is determined to be 15. The calculated natural population analysis shows that charges are transferred from Si n frames to Pt 2 atoms. Additionally, Pt 2 Si 19 cluster has the smallest HOMO-LUMO gap and the strongest chemical activity. [ABSTRACT FROM AUTHOR]

The stable equilibrium geometries, relative stabilities, and electronic and magnetic characteristics of Re n (n = 2–16) clusters were investigated by density functional theory method. The calculated fragmentation energies and second-order differences of energies exhibited interestingly that the stabilities of Re n (n = 2–16) clusters show a dramatic odd-even alternative behavior of the cluster size n: with the even-numbered Re n clusters being obviously more stable than their neighboring odd-numbered Re n clusters (beside n = 11). Simultaneously, the calculated HOMO-LUMO gaps of Re n (n = 6–16) display an oscillatory feature at large-sized Re n clusters. From the calculated magnetic moments and growth behaviors of Rhenium clusters, the magnetic Re 6 unit can be seen as the building block for the novel magnetic cluster-assembled nanomaterial. Such calculated results are in good agreement with the available experimental measurements. [ABSTRACT FROM AUTHOR]

Geometries, highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps, and magnetic and electronic properties of LnN 2 (Ln = La-Lu) systems are studied by using the density functional method with relativistic effect being taken into accounts. Interestingly, the optimized geometries exhibit that Rare earth Ln atom is favored of adsorptions of N 2 with end-on or side-on form. According to the calculated magnetic moments of LnN 2 (Ln = La-Lu), it is apparently shown that total magnetic moments mainly depend on the electrons filled in 4 f orbitals which generates magnetic properties of LnN 2 (Ln = La-Lu) clusters, GdN 2 has the biggest magnetic moment. The calculated natural populations of LnN 2 (Ln = La-Lu) systems show that the charges are transferred mainly from 6 s 2 to 5d orbitals. Most of 4 f subshell in LnN 2 is inert and hardly involves in chemical bonding, surprisingly, 4f orbitals of Pr atom involve in chemical bonding with N 2 molecule. [ABSTRACT FROM AUTHOR]

The geometries, stabilities, electronic properties, and bonding properties of the Hf-doped boron clusters at the size of n = 5–11 have been investigated systematically by using density functional theory. Emphasis is placed on studies that focus on the growth-pattern behaviors, dipole moments, fragmentation energies, aromatic properties, charge-transfer characteristics, and highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps. The optimized geometries show that thearomaticHf-encapsulated negative Bnstructures emerges as n = 10. The calculated fragmentation energies manifest that the magic numbers of stabilities are HfBn(n = 6, 9, and 11) and the HfB11is the most stable isomer of all different sized clusters. Natural population analysis shows that the charges transfer from Hf atom to boron framework. It should be pointed out that the remarkable charge-transfer features of HfBnclusters are obviously different from those of transitional metal (TM = W and Mo) doped Bnclusters. In addition, the calculated HOMO-LUMO gaps indicate that the HfBn(n = 5, 9, and 11) clusters have dramatically enhanced stabilities; meanwhile, the cage-like HfB11cluster is revealed and has the largest chemical hardness. [ABSTRACT FROM AUTHOR]

Geometries associated with relative stabilities and energy gaps of W@B n ( n = 20, 24, 28, 32) are systematically investigated by density functional theory. The calculated averaged atomic binding energies reveal that the W@B 20 has enhanced stability over other clusters. Interestingly, the irregular W@B 24 fullerene with bigger HOMO–LUMO gap is supposed to have stronger chemical activity. Moreover, the interactions between W and B24 cage is strongest one based upon the calculated binding energy between W and B cage, the doped W changes the properties of pure cages. The calculated dipoles of W@B n reveal that the irregular W@B 24 cage is a nonpolar molecule. [ABSTRACT FROM AUTHOR]

Bond lengths, vibrational frequencies, electron affinities, magnetic properties, and ionization potentials of the neutral and charged LnSi (Ln =La-Lu) diatom were studied by using the density functional method with relativistic effect being taken into account. Ground state was assigned for each species. The calculated natural populations of LnSi (Ln =La-Lu) exhibit that the charges are transferred mainly from 6 s to 5 d,and most of 4 f subshell in LnSi is inert without involving chemical bonding. The calculated highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps show that the HOMO-LUMO gaps are increased and exhibit oscillating behavior from LaSi to LuSi. Interestingly, total magnetic properties of LnSi (Ln =La-Lu)diatoms depend on the localized 4 f electrons which generate the magnetic moment of LnSi diatoms; additionally, the magnetic moment of EuSi is 11 μ which is the highest one. Comparisons with the available experimental and theoretical values are made and a good agreement is reached. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: The geometrical and electronic properties and growth patterns of the bimetal Pd2 doped Sin (n=10–20) clusters have been studied systematically by density functional theory. The growth-pattern behaviors, relative stabilities, and chemical bonding of these clusters are presented and discussed. The optimized geometries exhibit that the dominant growth patterns of Pd2Sin (n=10–20) are based on the pentagonal prism PdSi10. The bimetal Pd2 is doped on the opened cage-like silicon clusters (Sin) with the range of size n=10–15, while doped on bigger silicon clusters (Sin, n=16–20), the Pd2 are completely encapsulated inside Sin frames. The geometrical configurations of the encapsulated Pd2 in the Sin frames are varied due to the interactions between Pd2 and Sin frames. The calculated fragmentation energies reveal that the remarkable stable Pd2Sin clusters with n=11, 13, 16, 18, and 20 are observed. Among all different-size clusters, the Pd2-doped Si16 is the most stable cluster. Particularly, the cage-like Pd2Si16 geometry is obviously distinct as compared to the single transition metal doped silicon cluster. Interestingly, the critical size of geometry transition is explored at n=16. Natural population analysis manifests that the charge-transfer phenomena in the Pd2-doped Sin clusters are similar to those of the single TM doped silicon clusters. In addition, the Pd2Sin (n=10, 13, 14, 16, and 17) isomers have enhanced chemical stabilities because of their larger gaps between the highest occupied orbital and the lowest unoccupied orbital. [Copyright &y& Elsevier]

The geometries, stabilities, and antioxidant activities of L-Ascorbic acid (1a), D-erythroascorbate (2a), and D-erythroascorbate glucoside (3a) as well as their sulfur and selenium derivatives are systematically investigated by using density functional theory. Emphasis is placed on studies of the two main mechanisms, that is, hydrogen atom donation and single-electron transfer, and the O-H bond dissociation enthalpy and the ionization potential are computed in the gas phase and water solution. The calculated results indicate that the 2-OH group in the five-membered ring acts as an important H atom donor to free radicals. The 2-OH radical spin density distribution shows that the unpaired electron is mostly located at the C3 atom of the five-membered ring and partially at the vicinal O atoms, proving that a certain delocalization of the odd electron is effective in the five-membered ring. In water aqueous solution, the antioxidant capacity and the electron donating ability are increased as the O atom in the five-membered ring of 1a, 2a, and 3a is replaced by S and Se, respectively, in good agreement with experimental measurements; Furthermore, their antioxidant capacities are enhanced as compared with the standard antioxidant (resveratrol). © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Geometries and electronic properties of Eu 12 and (EuX) 12 (X = N, O, and S) cages with D 2h symmetry are investigated by first-principles density functional theory with Perdew-Burke-Ernzerhof exchange-correlation. The calculated total magnetic moments of stable (EuX) 12 (X = N, O, and S) and Eu 12 cages are respective 18, 20, 14 and 26 μ B. Their stability and electronic states for (EuN) 12 , (EuS) 12 , (EuO) 12, and Eu 12 cages are predicted, the coatings of N, O, and S atoms give rise to attenuation effect to magnetic moments and enhance stabilities of Eu 12 cage. The narrowband features of (EuX) 12 cages can be applied in solar cell and spintronic devices. [ABSTRACT FROM AUTHOR]