B12N12纳米笼：潜在的二氧化氮检测传感器

利用密度泛函理论通过计算吸附能量、HOMO/LUMO能隙变化、电荷转移、结构扭曲等研究二氧化氮分子在B12N12纳米笼的吸附．此外,通过计算B₁₂N₁₂的电子结合能、Gibbs自由能、态密度和分子表面的静电势研究其稳定性和其它特性．B₁₂N₁₂纳米笼吸附二氧化氮显示三种构型．B₁₂N₁₂团簇的HOMO/LUMO能隙变化对二氧化氮分子的存在非常敏感,从自由团簇的6.84 eV降为NO₂/团簇稳定团簇的3.23 eV．团簇的导电性被极大地提高,表明B₁₂N₁₂纳米簇可能是潜在的二氧化氮气体分子检测传感器.     

A DFT study on the formaldehyde (H2CO and (H2CO)2) monitoring using pristine B12N12 nanocluster

The interaction between formaldehyde monomer (H₂CO) as well as dimer ((H₂CO)₂) and pristine B₁₂N₁₂ nanocluster is investigated at B3LYP/6-311++G(d,p) level of theory. It is found that in contrary to the pristine boron nitride nanotube and nanosheet, formaldehyde adsorption induce considerable variation in the electronic properties of the B₁₂N₁₂ nanocluster. Also it is shown that the pristine B₁₂N₁₂ cluster could adsorb up to four monomer and three dimer of formaldehyde molecules in which the HOMO–LUMO gap decreased about 38–55%. Since the conductivity of the B₁₂N₁₂ nanocluster changes by the adsorption of formaldehyde molecules, the presence of this toxic gas could be detected. The Bader theory of atoms in molecules (AIM) is also applied to analyze the interaction of formaldehyde with nanocluster. It is suggested pristine B₁₂N₁₂ nanocluster could be a promising candidate for detecting formaldehyde molecule. The results indicate that B₁₂N₁₂ may be a promising chemical sensor for detection of formaldehyde molecule.     

Interaction of different types of nanocages (Al12N12, Al12P12, B12N12, Be12O12, Mg12O12, Si12C12 and C24) with HCN and ClCN: DFT,TD-DFT,QTAIM, and NBO calculations

In this work, the ability of different types of nanocages including Al₁₂N₁₂, Al₁₂P₁₂, Be₁₂O₁₂, B₁₂N₁₂, Si₁₂C₁₂, Mg₁₂O₁₂ and C₂₄ for the adsorption and detection of poisonous gases HCN and ClCN has been investigated, theoretically using the D3 dispersion corrected density functional theory (DFT-D3). The absorption spectra of HCN–nanocage and ClCN–nanocage complexes were calculated by the time-dependent density functional theory (TD-DFT) and compared with the calculated absorption spectrum of isolated nanocage to investigate the ability of nanocage for sensing of HCN and ClCN gases. It was found that the strongest interaction between HCN (ClCN) molecule and nanocage takes place when the molecule is adsorbed via its N atom on the surface of nanocage except for C₂₄. Also, it was shown that the Al₁₂N₁₂ is the best adsorbent for HCN and ClCN gases among the selected nanocages and Si₁₂C₁₂ is the best sensor for the detection of these gases using the electroconductivity and absorption spectroscopy techniques.     

Geometric and electronic structures of B12C6N6 fullerene

An electron deficient fullerene B₁₂C₆N₆ is studied by using ab initio calculations. The structure is generated by replacing N with C in the B₁₂N₁₂ cage to ensure only B–C and B–N bonds are formed. All the possible isomers are optimized and the low energy structures are determined. C and N atoms in the low energy isomers are inclined to segregate and form B₂C₂ and B₂N₂ squares. Natural bond analysis shows that the atomic orbitals of B, C and N in this cage hybrid approximately in sp^2.3 and then form B–C and B–N bonds. The 2p orbitals perpendicular to the cage surface are partially occupied and the molecular orbitals formed by these orbitals are highly delocalized. The natural charge on N is about −1.17 in both B₁₂N₁₂ and B₁₂C₆N₆, and the charge on C is −0.72 to −0.60. The molecular orbital compositions show that the B–N bonds are the same in B₁₂N₁₂ and B₁₂C₆N₆, and the B–C bonds possess stronger covalent character. The HOMO of B₁₂C₆N₆ is formed by 2p of B and C, and the LUMO is formed by 2p of C. The energy gap of C₂₄, B₁₂N₁₂ and B₁₂C₆N₆ is 2.52, 6.84 and 3.22 eV, respectively.     

Effects of endohedral element in B24N24 clusters on hydrogenation studied by molecular orbital calculations

Possibility of hydrogen gas storage in boron nitride (BN) clusters was investigated by molecular orbital calculations. Chemisorption calculation was carried out for B₂₄N₂₄ with changing endohedral elements in BN cluster to compare the bonding energy at nitrogen and boron, which showed that Li is a suitable element for hydrogenation to B₂₄N₂₄.     

Atomic and electronic structures and thermal stability of boron-nitrogen nanopeapods: B<Subscript>12</Subscript>N<Subscript>12</Subscript> fullerenes in BN nanotubes

The atomic structures, energies of formation, electronic structures, and thermal stabilities (in the temperature range T = 0–3000 K) of novel hybrid boron-nitrogen nanostructures (so-called nanopeapods B₁₂N₁₂@BN-NT) are simulated using the self-consistent density functional tight-binding (DFTB) method. The B₁₂N₁₂@BN-NT nanopeapods are regular linear ensembles of B₁₂N₁₂ boron-nitrogen fullerenes encapsulated in boron-nitrogen nanotubes (BN-NT), such as the (14, 0) nonchiral zigzag BN nanotubes, the (8, 8) nonchiral armchair BN nanotubes, and the (12, 4) chiral BN nanotubes.     

Formation of Boron Nitride Nanostructures by Means of 60keV N2+ Ion Beam Bombardment

The formation of bended BN nanostructures and small BN cage-like molecules, under Nc2+ ion-bombardment of BN samples, is reported. The analysis of high-resolution transmission electron microscopy indicates that bending the flat sp2 layers with strain or lattices defects directly under the mechanical deformation forms these BN nanostructures. In addition, the cages in diamlter range from about 0.4 to 1.8nm, closing to those of the B₁₂ N₁₂, B₁₆N₁₆, and B₂₀₈N₂₀₈ octahedral, were observed. The origins of the bended BN sheets and small BN cages were discussed based on the viewpoint of beam-solid interaction.     

Formation of small single-layer and nested BN cages under electron irradiation of nanotubes and bulk material

12 N₁₂, B₁₆N₁₆ and B₂₈N₂₈ octahedra which were predicted to be magic clusters for the BN system from electronic structure calculations. Received: 2 March 1998     

Theoretical study on structure of boron nitride fullerenes

We propose the parameters of the Stillinger-Weber potential for hexagonal boron nitride (BN) structures. For the reliability of these parameters, the structural property of BN fullerenes is investigated. The stability of BN fullerenes increases with increasing the number of atoms, due to the reduction of the curvature effect of BN fullerenes. The structures of the relative stable fullerenes are B₁₆N₁₆, B₁₈N₁₈, B₂₂N₂₂, B₂₅N₂₅, and B₂₈N₂₈.     

Molecular Dynamics Simulations of Adsorption of Polymer Chains on the Surface of B<Subscript>m</Subscript>N<Subscript>n</Subscript> Graphyne-Like Monolayers

Molecular dynamics simulations are used here to study the interactions between B_mN_n graphyne-like monolayers and four different polymer chains. BN, B₁N₉, and B₂N₈ graphyne-like monolayers are selected from the family of B_mN_n graphyne-like monolayers. It is observed that increasing the number of B atoms in the structure of B_mN_n graphyne-like monolayers results in larger interaction energies of nanosheet/polymer systems. It is also shown that the polymer chains with the linear adsorbed configurations on the nanosheets have larger interaction energies with the nanosheets. Investigating the effect of number of polymer repeat units on the polymer/nanosheet interaction energy, it is observed that increasing the number of repeat units of polymers leads to enhancing the polymer/nanosheet interaction energy.     

B12@B12@B60 and B12@(B12)12 giant clusters with doping atoms observed by high-resolution electron microscopy

B₁₂@B₁₂@B₆₀ and B₁₂@(B₁₂)₁₂ giant clusters consisting of B₁₂-based icosahedral clusters in B₁₀₅Al_2.6Cu_1.8 and B₅₆Y crystals were directly observed by high-resolution electron microscopy, image calculation and crystallographic image processing. Doping atom positions such as Al, Cu, and Y were also detected in the high-resolution images. The present work indicates that the cluster arrangements with light element of boron could be detected by using the crystallographic image processing technique.     

Mustard gas adsorption on the pristine and BN-doped graphynes: A computational study

The electronic sensitivity and reactivity of pristine, and BN doped graphyne (BNG) are scrutinized toward mustard gas using DFT calculations. The mustard gas weakly adsorbs via its Cl atom on the graphyne with adsorption energy about -3.1 kcal/mol and has no effect on its electrical conductivity. Replacing –C≡C– linkages with isoelectronic –BN– linkages increases the HOMO-LUMO gap (E_g) and decreases the work function and reactivity of graphyne. By mustard adsorption, the E_g of BNG decreases from 2.24 to 1.12 eV, increasing the electrical conductivity. Also, the BNG work function is considerably affected, changing the field emission electron current. Finally, a short recovery time about 0.03 s at room temperature is predicted for the mustard desorption from the surface of BNG. We also showed that the electrical conductivity change relates to the mustard concentration. The results indicate that the BNG may be a promising sensor for mustard gas.     

Adsorption of mercaptopurine drug on the BN nanotube,nanosheet and nanocluster: a density functional theory study

ABSTRACT

We have investigated the interaction of mercaptopurine (MP) drug with BN nanotube, nanosheet and nanocluster using density functional theory calculations in the gas phase, and aqueous solution. We predicted that the MP drug tends to be physically adsorbed on the surface of BN nanosheet with an adsorption energy (E_ad) about ?3.2?kcal/mol. The electronic properties of BN nanosheet are not affected by the MP drug, and this sheet is not a sensor. But the electronic properties of BN nanotube and nanocluster are significantly sensitive to this drug in both gas phase, and aqueous solution. The BN nanocluster suffers from a long recovery time (8.8?×?10⁸?s) because of a strong interaction (E_ad?=??28.6?kcal/mol), and this cluster is not a proper sensor for MP detection. But the BN nanotube benefits from a short recovery time about 49.5?s at room temperature, and may be a promising candidate for application in the MP sensors. The water solvent decreases the strength of interaction between the BN nanotube, and MP drug, but it does not affect the electronic sensitivity of the nanotube sensibly.     

Ga6N6团簇结构性质的理论计算研究

在密度泛函理论的基础上，对Ga₆N₆团簇进行了第一性原理、全电子、从头计算，得到了10种可能的三维空间结构及其电子结构.其中最稳定结构的一对GaN原子的平均结合能为9.748 eV，因此是可能存在的.但与他人计算的Ga₃N₃和Ga₅N₅相比，Ga₆N₆团簇可能不属于“幻数”团簇.最稳定结构的Ga₆N_{6 关键词： GaN 团簇 电子结构}     

Determination of H2S,COS, CS2 and SO2 by an aluminium nitride nanocluster: DFT studies

ABSTRACT

Density functional theory calculations were used to investigate the potential application of an AlN nanocluster in the detection of H₂S, COS, CS₂ and SO₂ gases. In overall, the order of strength of interaction of these gases with the nanocluster is as follows: SO₂ (E_ad?=??17.6?kcal/mol)?>?H₂S (E_ad?=??14.0?kcal/mol)?>?COS (E_ad?=??8.4?kcal/mol)?>?CS₂ (E_ad?=??4.5?kcal/mol). This indicates that by increasing the electric dipole moment, the adsorption energy becomes more negative. We found that the Al₁₂N₁₂ nanocluster may be a promising work function-type sensor for SO₂ gas among the studied gases. Also, it is an electronic sensor for both SO₂ and CS₂ gases but selectively acts between them because of their different effects on the electrical conductivity. It is neither work function-type nor electronic sensor for H₂S and COS gases. The AlN nanocluster benefits from a short recovery time about 7.7?s and 18.0?ms for desorption of SO₂ and CS₂ gases from its surface at room temperature, respectively. It is also concluded that this cluster can work at a humid environment.     

The Hartree-Fock exchange effect on the CO adsorption by the boron nitride nanocage

We studied the effect of Hartree-Fock (HF) exchange percentage of a density functional on the adsorption properties and electronic sensitivity of the B₁₂N₁₂ nanocluster to CO molecule. It was found that by an increase in the %HF, the LUMO level is nearly constant while the HOMO level is strongly stabilized, expanding the HOMO-LUMO gap (E_g). Also, the volume of the all structures decreased and the sensitivity of the B₁₂N₁₂ is slightly increased to CO molecule. For the pristine B₁₂N₁₂ cluster, the B66 and B64 bonds are about 1.43 and 1.49 Å at 10% HF, and 1.23 and 1.26 Å at 100% HF, respectively. The HF exchange between 10–20% may predict an accurate E_g for the B₁₂N₁₂ system. We concluded that functionals with a large %HF such as M06-HF, and M06-2X may significantly overestimate the E_g, and bond strength. We obtained a parabolic relationship between the %HF and the adsorption energy of CO molecule on the B₁₂N₁₂ cluster. Also, an increase in the %HF predicts a larger charge transfer from the CO molecule to the cage.     

ELECTRONIC STRUCTURE OF CLUSTER-ASSEMBLED Al12C (Si) SOLID

The electronic structures of the cluster-assembled solid Al₁₂C(Si) are studied by the ab initio method. We find that Al₁₂C(Si) can solidify into a van der Waals solid. The electronic band structures show very weak dispersion. The main features in the electronic structure of cluster are retained in the solid, and an energy gap up to about 1.5 eV is observed for Al₁₂C and Al₁₂Si solids.     

Hydrogen incorporation into BN fullerene-like nanostructures: A first-principles study

We performed density functional theory calculations to investigate the possibility of formation of endohedrally H@(BN)_n–fullerene (n: 24, 36, 60) and H@C₆₀ complexes for potential applications in solid-state quantum-computers. Spin-polarized approach within the generalized gradient approximation with the Perdew–Burke–Ernzerhof functional was used for the total energies and structural relaxation calculations. The calculated binding energies show that H atom being incorporated into B₆₀N₆₀ nanocage can form most stable complexes while the B₂₄N₂₄ and C₆₀ nanocages might form unstable complex with positive binding energy. We have also examined the penetration of an H atom into the respective nanocages and the calculated barrier energies indicate that the H atom prefers to penetrate into the B₂₄N₂₄ and B₆₀N₆₀ nanocages with barrier energy of about 0.47 eV (10.84 kcal/mol). Furthermore the binding characteristic is rationalized by analyzing the electronic structures. Our findings reveal that the B₆₀N₆₀ nanocage has fascinating potential application in future solid-state quantum-computers.     

DFT study of boron trichloride adsorption on the surface of Al12N12 nanocluster

In the present study, ability of Al₁₂N₁₂ nanocluster as a new adsorbent for boron trichloride is studied by using density functional theory (DFT) calculations. Two distinct relaxed geometries of Al₁₂N₁₂-BCl₃ complex are located. The dominant configuration (B) involves chemisorption of BCl₃ on aluminum nitride nanocluster with an adsorption energy of ?303 kJ/mol compared to ?33 kJ/mol for a less favourable configuration A (based on wB97XD functional). The enthalpy and Gibbs free energy of interaction for each relaxed was also analysed for better understanding of the thermochemistry of adsorption process. The charge transfer analysis reveals opposing trend in both configurations. Configuration A showed transfer of charge from BCl₃ to nanocluster (+0.123 e), whereas reverse direction of charge transfer was found for the other configuration (?0.083 e). Furthermore, the frontier molecular orbital as well as densities of states of all systems are analysed to follow the changes in the electronic structure of Al₁₂N₁₂ upon adsorption of BCl₃.     

Structural and electronic properties of zinc blende BxAl1−xNyP1−y quaternary alloys via ?rst-principle calculations

The structural and electronic properties of cubic zinc blende BN, BP, AlN and AlP compounds and their B_xAl_1−xN_yP_1−y quaternary alloys, have been calculated using the non relativistic full-potential linearized-augmented plane wave FP-LAPW method. The exchange-correlation potential is treated with the local density approximation of Perdew and Wang (LDA-PW) as well as the generalized gradient approximation (GGA) of Perdew-Burke and Ernzerhof (GGA-PBE). The calculated structural properties of BN, BP, AlN and AlP compounds are in good agreement with the available experimental and theoretical data. A nonlinear variation of compositions x and y with the lattice constants, bulk modulus, direct and indirect band gaps is found. The calculated bowing of the fundamental band gaps is in good agreement with the available experimental and theoretical value. To our knowledge this is the first quantitative theoretical investigation on B_xAl_1−xN_yP_1−y quaternary alloy and still awaits experimental confirmations.