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The correct description of the weak interaction between small molecules and oxide surfaces is still a challenge for theory. In the present review, the current status of the cluster approach to the calculation of adsorption geometries and energies by means of quantum-chemical ab initio methods is discussed. In the first part, the physical and chemical contributions to the bonding mechanism are briefly...
Carbon nanotubes based sensors are gaining popularity due to their high selectivity, sensitivity, fast response and recovery time, low operating temperatures and low power consumption. However, due to a strong sp2 carbon-carbon bonding within CNTs, the interaction between defect free CNT walls and gas molecules had been expected to be relatively weak and consequently, the electronic transport properties...
The adsorption of nitrogen on wurtzite ZnO (0001) surface were studied by First-principles. Different adsorption sites and the effect of different coverages have been considered. The clean ZnO (0001) surface and different coverages of Nitrogen adsorbed on wurtzite ZnO(0001) surface show n-type conduction. We found that the H3 adsorption site is energy-favored in each coverage considered, and that...
We have applied extensive ab initio density functional theory coupled with non-equilibrium Green's function (DFT/NEGF) and molecular dynamics simulations to study the details of physical interactions between carbon nanotubes and amino acids in order to understand the underlying mechanisms that contribute to changes in electronic transport of carbon nanotubes in a two-terminal configuration. It was...
In this paper, the structural and electronic properties of Cs adsorption on GaAs surface were studied. The samples were prepared by MBE. The conduction bands, valence bands, band structure and density of states were calculated by first principles based on density functional theory. The effect of Zn doping on electronic structure were also analyzed.
Transition metal (TM) oxide clusters have attracted enormous attention because of their novel structural, electronic, magnetic and catalytic properties, different from the corresponding bulk solids. For instance, The structures of (V2O5)n (n = 2-5, 8, 10, 12) gas-phase clusters are most stable in polyhedral cage very different from the layer structure of the solid bulk. PES combined with density functional...
In this paper, the complex of Fe4 cluster and single walled carbon nanotubes (SWCNTs) as a model system of metal cluster-SWCNT complexes is presented. Structural and mechanical properties of the Fe4 cluster adsorbing inside and outside SWCNTs with various chiralities are investigated by first-principles calculations.
Summary form only given. The influence of alkali-metal adsorption positions and defects positions on work functions of (5, 5) single-walled carbon nanotubes (CNTs) with a capped edge had been investigated by first-principles calculations. An single-walled armchair (5, 5) CNT with a capped edge was assumed. A single vacancy defect was created by removing a carbon atom from different atomic layers (which...
We present a theoretical model for electrical double layers formed by ion adsorption in nanoscale carbon pores. In this work a combination of computational methods, including first-principles and classical modeling, are used to explain the onset of an anomalous increase in capacitance for small pores. The study highlights the key role played by pore curvature and nanoconfinement on the capacitance...
The characteristics of hydrogen adsorption on Li metal atoms dispersed on graphene with boron substitution were investigated for Li clustering, hydrogen bonding characteristics and open metal states of Li adatom by using density functional theory calculations. It is found that Li atoms are well dispersed on boron substituted graphene and can form the (2 ?? 2) pattern because clustering of Li atoms...
First-principles density functional theory (DFT) calculations using the generalized gradient approximation (GGA) have been used to expand the analysis of the adsorption properties of polynitrogen and high nitrogen compounds on Al(111) and AlN(0001) surfaces. The electron-ion interaction has been described using ultrasoft (PAW) pseudopotentials in the case of Al (AlN). All calculations have been done...
Further progress in examining the suitability of carbon nanotubes for single-biomolecule sensing has been made via ab initio simulations using the density functional theory/non- equilibrium green's function approach. Adsorption of different amino acids on short carbon nanotubes is predicted to cause different changes in local densities of states, transmission coefficient, and current.
We perform first principles total energy calculations to investigate the atomic structure of the adsorption of Pt on Ge(001) surfaces. Our studies are carried out using the periodic density functional Theory. The exchange and correlation energies are treated within the generalized gradient approximation according to the Perdew, Burke, Ernzerhof revised parameterization. The initial atomic structure...
First-principles density functional theory (DFT) calculations using the generalized gradient approximation (GGA) have been performed to study the adsorption of a series of all-nitrogen and high-nitrogen compounds of increasing sizes and complexity on the Al(111) surface. The calculations employ periodic slab models with 4 Al layers, ranging in size from (3times3) to (5times5) surface unit cells, and...
We investigated wire-mesh media with plasmalike dispersion of dielectric permittivity as a potential medium for nanoplasmonic sensors utilizing adsorption of chemical, biochemical or biological analytes. Such structures belong to the ultra-low refractive index metamaterials and are typically used as one of the building blocks for zero- or negative index metamaterials. We analyzed a 2D array or conductive...
An ab initio approach of Car-Parrinello molecular dynamics is used to study the chemisorption of a single oxygen atom on outer surface of zigzag single-wall carbon nanotubes under various uniaxial strains and bending deformation. The effect of mechanical deformation on adsorption of oxygen atom on CNT is demonstrated by linking the chemical reactivity and structural deformation. The adsorption energy...
First principle calculations of Ag nanoslab optical functions indicate strong contributions of the surface states to light absorption. Imaginary part of dielectric function responsible for losses is substantially modified due to adsorption of organic molecules.
The electronic structures and surface diffusion of atoms in bcc Cr/Fe (001) and Fe/Cr (001) were quantitatively investigated using first principles based on density functional theory (DFT). Adsorption energies on hollow site and bridge site were calculated. Cr atom on hollow site of ferromagnetic Fe substrate, spontaneously aligned its spin direction anti-parallel to the substrate magnetization, and...
In this study, the surface formation energy and electronic structure for the gas atom (H-, C-, or O-adatom) adsorbed on the Ga-terminated (0001 macr) surface in a condition of nitrogen vacancy were extensively investigated using ab initio calculations.
The electronic structures of the self-assembled monolayers (SAMs) of n-alkanethiolate [CH3(CH2)nS, n=1-5] on Au(111) surface have been investigated using the state-of-the-art first-principles calculations. The adsorption energy, the tile angle, and the partial charge of n-alkanethiolate were presented. The charge transfer at the metal-molecule interface was calculated by the Mulliken population analysis...
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