1,721,029 research outputs found
Dynamics at a Peptide-TiO2 Anatase (101) Interface
No full textThe interface between biological matter and inorganic materials is a widely investigated research topic due to possible applications in biomedicine and nanotechnology. In this context, the molecular level adsorption mechanism that drives specific recognition between small peptide sequences and inorganic surfaces represents an important topic likely to provide much information useful for designing bioderived materials. Here, we investigate the dynamics at the interface between a Ti-binding peptide sequence (AMRKLPDAPGMHC) and a TiO2 anatase surface by using molecular dynamics (MD) simulations. In the simulations the adsorption mechanism is characterized by diffusion of the peptide from the bulk water phase toward the TiO2 surface, followed by the anchoring of the peptide to the surface. The anchoring is mediated by the interfacial water layers by means of the charged groups of the side chains of the peptide. The peptide samples anchored and dissociated states from the surface and its conformation is not affected by the surface when anchored. (Figure Presented). © 2017 American Chemical Society
CHEMICAL BOND AND INTERFACES STATES AT METAL-SEMICONDUCTOR AND INSULATOR-SEMICONDUCTOR INTERFACES
No full textLMTO Calculation
Chemical bond and electronic states in the CaF2-Si(111) and Ca-Si(111) interfaces
Full text linkThe first stage of formation of the CaF2-Si(111) and Ca-Si(111) interfaces is studied through the employment of the surface linear-muffin-tin-orbital approach in the atomic-sphere approximation. The interfaces are simulated by monolayers of F-Ca and Ca on Si(111), respectively. Both valence- and core-electron states have been calculated: their analysis gives important information about the nature of the Ca-Si and Ca-F bonds. These results are successfully compared with the available experimental data. The importance of considering the Madelung contribution in the interpretation of surface-core-level shifts is pointed out
On-site correlation in valence and core states of ferromagnetic nickel
No full textWe present a method which allows us to include narrow-band correlation effects in the description of both valence and core states and we apply it to the prototypical case of nickel. The results of an ab initio band calculation are used as input mean-field eigenstates for the calculation of self-energy corrections and spectral functions according to a three-body scattering solution of a multiorbital Hubbard Hamiltonian. The calculated quasiparticle spectra show a remarkable agreement with photoemission data in terms of bandwidth, exchange splitting, satellite energy position of valence states, and spin polarization of both the main line and the satellite of the 3p core level
THE ELECTRONIC-PROPERTIES OF THE CAF2-SI(111) SYSTEM - FROM MONOLAYER COVERAGE TO SOLID SOLID INTERFACE
No full textThe surface linear muffin-tin method in the atomic-sphere approximation (SLMTO-ASA) is applied to study the electronic properties of the CaF2-Si(111) interface. We investigate the growth of CaF2 on Si(111) following the interface formation from low to high coverages. The early stages of the growth are simulated by an interface formed by a monolayer of Ca deposited on Si(111) followed by a F layer, i.e., a F-Ca-Si(111) system. Both valence- and core-electron states have been calculated. Their analysis gives important information about the nature of the Ca-Si and Ca-F bonds. We explore the dependence of the electronic properties on the number of deposited layers showing that the main contribution to the interface properties is established at monolayer coverage and that the transfer of charge between the two crystals is localized in their last layers
Adsorption of Modified Arg, Lys, Asp, and Gln to Dry and Hydrated ZnO Surface: A Density Functional Theory Study
No full textThe interface of biological molecules with inorganic surfaces has been the subject of several recent studies. Experimentally some amino acids are evidenced to play a critical role in the adhesion and selectivity on oxide surfaces; however, detailed information on how the water molecules on the hydrated surface are able to mediate the adsorption is still missing. Accurate total energy ab initio calculations based on dispersion-corrected density functional theory have been performed to investigate the adsorption of selected amino acids on the hydrated ZnO(101 ̄0) surface, and the results are presented and discussed in this paper. We have also investigated the role played by water in the determination of the most energetically favorable adsorption configurations of the selected amino acids. We have found that for some amino acids the most energetically favorable configurations involve the deprotonation of the molecule if the water screening is not effective. © 2015 American Chemical Society
Band-structure effects in the core-level photoemission spectra of NiO
No full textCalculation of Ni 2p photoelectron spectra for NiO has been performed within a picture which takes into full account the itinerant character of valence electrons and the localized many-body interaction between core and valence electrons. The results of an nb initio band-structure calculation are used as an input for the calculation of self-energy correction and spectral function according to a three-body scattering solution of a many-body Hamiltonian which includes the Coulomb repulsion between core and valence states. The calculated spectrum shows, in agreement with experimental data, a doubly peaked main line which can be attributed to two independent relaxation processes involving valence-baud Ni d states of either pure or hybridized orbital character
Covalency on the adsorption of Na on Si(111)
No full textABSTRACT The linear muffin-tin orbitals method in the atomic-sphere approximation is employed to investigate the electronic structure of a semiconductor-metal interface at monolayer coverage. We studied the interface formed by one monolayer of Na adsorbed on Si(111). Analysis of both valence- and core-electron states gives information on the nature of the bond between Na and the Si surface, which is mainly covalent, and allows one to interpret the available experimental data
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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