Theoretical Study of the Structural,Electronic, and Magnetic Properties of Zirconium-doped Aluminum Clusters:Al_nZr(n = 1～14)

The geometrical structures, stabilities, electronic and magnetic properties of Al_nZr(n = 1~14) clusters have been systematically investigated using density functional theory. It is found that for the optimized clusters the zirconium atom prefers to remain on the surface, and the growth patterns are organized as follows: Zr substituted Al_(n+1) clusters or Zr capped Aln clusters as well as Al added Al_(n-1)Zr clusters. All doped clusters exhibit relatively larger average binding energies and magnetic behaviors compared with pure Al_(n+1) counterpart. The calculated fragmentation energies and second-order difference of energies exhibit pronounced odd-even alternation behavior as a function of the cluster size when n = 3~13. In all Al_nZr clusters, there exits internal hybridization in both Al and Zr atoms and charge transfer from Al to Zr atom, which reflects the strong interactions between the two kinds of atoms. The magnetic property analysis shows that the 4d electrons of Zr atom are the main origin for cluster magnetism.     

Density Functional Study of Structural and Electronic Properties of Small Bimetallic Silver—Nickel Clusters

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.     

Density Functional Theory Study on the Structural and Electronic Properties of Ge（SiO_2）_n Clusters

The geometry,stability,binding energy and electronic properties of(SiO2)n and Ge(SiO2)n clusters(n = 7) have been investigated by Density functional theory(DFT).The results show that the lowest energy structures of Ge(SiO2)n are obtained by adding one Ge on the end site of the O atom or the Si near end site of the O atom in(SiO2)n.The chemical activation of Ge-(SiO2)n is improved compared with(SiO2)n.The calculated second-order difference of energies and fragmentation energies show that the Ge(SiO2)n clusters with n = 2 or 5 are stable.     

Structural and Electronic Properties of Lutetium Doped Germanium Clusters LuGen(+/0/-)(n=6～19):A Density Functional Theory Investigation

Structural growth mechanism,energetics,and electronic properties of cationic,neutral,and anionic lutetium doped germanium cluster LuGen(+/0/-)(n=6～19)were compr...     

Nonorthogonal Tight-binding Study of the Geometries and Electronic Properties of Ge_n(n=2—20)Clusters

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DFT Studies on the Stoichiometric Thorium Oxide Clusters(ThO_2)_n(n = 1～5): Electronic and Structural Properties

Density functional theory(DFT) calculations are performed to investigate the electronic and structural properties of the stoichiometric thorium oxide clusters(ThO_2)_n-/0(n = 1～5). Generalized Koopmans' theorem is applied to predict the vertical detachment energies(VDEs)which are used to simulate the anionic photoelectron spectra(PES). Molecular orbital analyses are performed as well to analyze the chemical bonding in these thorium oxide clusters. The results show that the ground states of(ThO_2)_n-/0(n = 1～5) clusters prefer the low-spin structures. With increasing of the cluster size(n), the structure parameters of(ThO_2)_n-/0(n = 1～5) gradually evolve toward bulk thorium oxide species. It shows that both the coordination number and the average bond length increase gradually in(ThO_2)_n-/0(n = 1～5) to approach that of ThO2 bulk. What's more, the vibration frequencies of Th=O double bonds are found to be decreasing along with the increased cluster size.     

Density Functional Study of AunCo (n=1～7)

Cobalt-doped gold clusters Au_nCo (n=1～7) are systematically investigated for the possible stable geometrical configurations and relative stabilities of the lowest-lying isomers using density-functional theory at B3LYP/LanL2DZ level. Several low-lying isomers were deter-mined, and many of them are in electronic configurations with a high spin multiplicity. The results indicate that the ground-state Au_nCo (n=1～7) clusters adopt a planar structure except for n=7. The stability trend of the Au_nCo (n=1～7) clusters shows that the Au₂Co clusters are magic cluster with high stability.     

Probing Structure,Thermochemistry, Electron Affinity and Magnetic Moment of Dysprosium-doped Silicon Clusters DySi_n(n = 3～10) and Their Anions with Double-hybrid Density Functional Theory

The equilibrium geometries, electronic structures and electronic properties including adiabatic electron affinity(AEA), vertical detachment energy(VDE), simulated photoelectron spectroscopy, HOMO-LUMO gap, charge transfer, and magnetic moment for DySi_n(n = 3~10) clusters and their anions were systematically investigated by using the ABCluster global search technique combined with the B3 LYP and B2 PLYP density functional methods. The results showed that the lowest energy structure of neutral DySi_n(n = 3~10) can be regarded as substituting a Si atom of the ground state structure of Si_(n+1) with a Dy atom. For anions, the extra electron effect on the structure is significant. Starting from n = 6, the lowest energy structures of DySi_n~?(n = 3~10) differ from those of neutral. The ground state is quintuplet electronic state for DySi_n(n = 3~10) excluding DySi_4 and DySi_9, which is a septet electronic state. For anions, the ground state is a sextuplet electronic state. The reliable AEA and VDE of DySi_n(n = 3~10) are reported. Analyses of HOMO-LUMO gaps indicated that doping Dy atom to silicon clusters can improve significantly their photochemical reactivity, especially for DySi_9. Analyses of NPA revealed that the 4 f electrons of Dy in DySi_4, DySi_9, and DySi_n~? with n = 4 and 6~10 participate in bonding. That is, DySi_nbelongs to the AB type. The 4 f electrons of Dy atom provide substantially the total magnetic moments for DySi_n and their anions. The dissociation energies of Ln(Ln = Pr, Sm, Eu, Gd, Ho, and Dy) fromLn Sin and their anions were evaluated to examine the relative stabilities.     

Study of Structures and Electronic Properties of Pdn-1Pb and Pdn(n≤8) Clusters

Geometric and electronic properties of Pdn-1Pb and Pdn(n≤8) clusters have been studied by using density functional theory with effective core potentials, focusing on the differences between mono- and bimetallic clusters. The average bond length of Pdn-1Pb (n≤8) bimetallic clusters is longer than that of pure palladium clusters except for n = 2 and 3. The most stable structure of Pdn-1Pb (n≤7) is the singlet where there is at least a Pd or Pb atom on its excited state. The energy gaps of Pd-Pb binary clusters are narrower than those of Pdn clusters, and then the chemical activity is strengthened when Pdn clusters are doped with Pb.     

Structural, Electronic, and Magnetic Properties of MB n (M?=?Y, Zr, Nb, Mo, Tc, Ru, n?≤?8) Clusters

The geometries, stabilities, electronic, and magnetic properties of MB _n (M?=?Y, Zr, Nb, Mo, Tc, Ru, n????8) clusters have been systematically investigated by density functional theory. It is shown that the lowest energy structures of MB _n (n????3) clusters can be obtained by substituting one B atom in the lowest energy structures of B _n+1 clusters in most cases. After n????8, the 3D configurations prevail and become the lowest-energy structures. The second-order energy difference and the dissociation energy show YB₇, ZrB₇, NbB₆, MoB₆, TcB₆, RuB₆ clusters possess relatively higher stabilities. The doped-M atoms improve the chemical activity of the host clusters in most cases; but different M atom has different effect on B atom??s electronic structure. The binding strengths are strong between M and B _n , which plays an important role in the M?CB growth mechanisms. It is interesting that the relative orientation between the magnetic moments of the M (M?=?Zr, Nb, Mo, Tc, Ru) atoms and those of its neighboring B atoms exhibits ferromagnetic or antiferromagnetic alignment in contrast to the ferromagnetic alignment of YB _n .     

A Density Functional Study on the Geometries of Compounds Fe(HCN)n+(n = 1～6)

The possible geometries of Fe(HCN)n+ (n = 1～6) compounds were studied by using DFT/UB3LYP/6-31G(2df) method. The structure and ground state of each fragmental ion are C∞v (4∑+ or 6∑+), D∞h(4∑g+), D3h (4A1'), C2v or Td or C3v (4A1), and D3h (4A1') or C4v( (2A1') sequentially with n = 1～5. For the compound Fe(HCN)6+, the possible geometry was not obtained. The sequential incremental interaction energy (-△(△E)), dissociation energy (△D0), enthalpy (-△(△H)) and Gibbs free energy (-△(△G)), and frequencies for HCN-Fe(HCN)n-1+ were also calculated, and the results are all in good agreement with the experiments. The bond length of Fe-N is lengthened with the increase of cluster size, and the strength of Fe+-N coordination bond varies nonmon- tonically as increasing the number of ligands. The Fe+-N bond of Fe(HCN)2+ is the strongest in all compounds.     

Probing the Structures and Properties of Asymmetric Clusters (CH3ClBN3)n (n = 1–6) with Density Functional Theory

Russian Journal of Physical Chemistry A - The structures, stabilities, IR spectrum and thermodynamic properties of small asymmetric clusters (CH3ClBN3)n (n = 1–6) are probed using density...     

First-principle Study of AunSc (n=2～13) Clusters

The geometries, stabilities, electronic, and magnetic properties of Au_nSc clusters have been systematically investigated by density functional theory. The lowest energy structures of Au_nSc favor planar structure and the doped Sc atom does not disturb the frame of Au_nclusters with n≤11. For n≥12, Sc atom is fully encapsulated by the Au cages. From theanalysis of the second-order energy difference, the fragmentation energies, vertical ionizationpotential, vertical electron affinity, and HOMO-LUMO gap, the clusters with odd Au atoms possess relatively higher stabilities than their neighbor size. The doping of Sc atom can greatly improve the stability and change the sequence of chemical activity for Au_n. For n≤11, the total magnetic moments of Au_nSc appear the alternation between 0.00 and 1.00 μB. The total magnetic moments are quenched when Sc is trapped into the Au cages with n≥12.     

A Density Functional Study on the Geometries of Compounds Fe(HCN)_n~+ (n = 1～6)

1 INTRODUCTION The solvation of metal ion by different types ofsolvents is of great interest for a wide variety of app-lications[1]. In the experimental and theoretical inve-stigations, most of such studies are focused on ion-ligand systems complexed by…     

Electronic and Structural Properties of Neutral, Anionic, and Cationic Rh x Cu4−x (x = 0–4) Small Clusters: A DFT Study

In this study, electronic structure, stability, and tendency to exchange electron of neutral, anionic, and cationic Rh _x Cu_4?x (x = 0–4) small clusters were investigated by density functional theory calculations. For neutral small clusters, it was found that the most stable structures of Rh₄, Rh₃Cu and Rh₂Cu₂ have distorted tetrahedral shape while the most stable structures of RhCu₃ and Cu₄ have quasi-planer shape. Adding charges to the clusters, caused shapes of the most stable structures undergo variations. Stabilities of the neutral, anionic, and cationic clusters decrease linearly with increasing the copper content. In addition, calculated chemical harnesses indicated that the small cluster with 75 % copper content has the least chemical hardness. Interestingly, prevailing number of electronegative (Rh) and electropositive (Cu) atoms in the anionic and cationic clusters coincides with high dipole moment in these species that occur at 25 and 75 % copper respectively.     

Ceometries,Energetics and Spectroscopic Properties of Oxygen Clusters Oxy (x=2～6, y=-2～2)

The geometries, energetics and spectroscopic properties of oxygen clusters, Oxy(x=2~6, y=-2~2), were investigated at the B3LYP/6-311G (d, p) level. The CASSCF calculations were carried out for the ground and excited states of3O2and2O2+. The total energy is3O2(3Σg-)<2O2-(2Πgi)<1O2(1Δg)<1O2-2(1Σg+)<2O2+(2Πg)<1O2+2(1Σg+). The relative energy of the active doublet anion of oxygen molecule,2O2-(2Πgi), is only 28 kJ/mol higher than the triplet neutral oxygen molecule,3O2(3Σg-). The calculated O-O vibrational frequencies all are in good agreement with the experimental values. They are 1577 (1580), 1139 (1090), 1563 (1484), 627 (615~545) and 1993 (1905) cm-1, where the O-O vibrational frequency values in parentheses are experimental values, for3O2(3Σg-),2O2-(2Πgi),1O2(1Δg),1O2-2(1Σg+) and2O2+(2Πg), respectively. Moreover, the O-O vibrational frequency of1O2+2(1Σg+) was computed as 2368 cm-1which has not been reported before at both experimental and theoretical levels. Both bent and linear geometries of O3were studied. The bent-types of O3are more favorable than the linear-type in energy. Three types of structure for oxygen trimers are calculated at the B3LYP/6-311G (d, p) level. They are the structure-I with an obtuse angle of O-O-O,the structure-II with an acute angle of O-O-O, and the structure-III of linear type. For a bent-type structure of O3species (structure-I), the total enegy is2O3-(2B1)<1O3(1A1)<3O3(3B2)<1O3-2(1A1)<2O3+(2A1). The optimization of geometry at B3LYP/6-311G (d, p) level indicated that the species of2O3-(2B1) with 1.3573 of O-O bond length and 115.6584o of O-O-O bond anger is the ground state of O3. The total energy of O4species and their ions is2O4-(Cs,2A′, bend-type)<2O4-(C2v,2A2,face-centered triangle-type)<2O4-(D∞h,2Σg, linear-type)<1O4(Cs,1A′, bend-type)<1O4(D∞h,1Σg, linear-type)<1O4(D4h,1A1g, square-type)<1O4(C2v,1A1, face-centered triangle-type)<2O4-(D4h,1A1g, square-type)<2O4+(D∞h,2Σg, linear-type)<2O4+(Cs,1A′, bend-type). The species with the lowest relative energy is an anion,2O4-(Cs,2A′, bendtype), with chair form geometry and characteristic vibronic frequencies of 1179 and 1349 cm-1. The relative energy of1O5(C2v,1A1) with coplanar-triangle-bicone geometry is the lowest among the O5species and their ions, which may be a resonance structure with1O5(C2v,1A1) of A type. Their characteristic vibronic frequency is 1302 cm-1. The relative energy of the O6species and their ions with hexagon geometry is lower than one with linear geometry. Their infrared vi-bronic intensity may be weak and unobservable but the Raman vibronic intensity may be strong and observable based on their symmetry.     

A Density Functional Study of Small （NiTi）x Clusters with x=1-3

Systematic studies on the geometry, electronic structure and vibrational properties of small (NiTi)x clusters with x=1-3, within the framework of the density functional theory, were performed in this work. The electronic structure analyses were used to investigate the bonding between the early-late(EL) transition metals in their alloy. The results of our calculations have been used to predict (NiTi)x clusters structure for the ground state and confirm that s-electron density is transferred from Ti atoms to Ni atoms followed by the back donation of electrons through the d-orbital. The study provides a fragment approach based on the isolobal analogy that NiTi molecular fragments play a significant role in forming clusters.