Watching graphene grow The growth of on metal surfaces can be catalyzed by mobile surface atoms. Patera et al. used a high-speed scanning tunneling microscope to image the islands nickel surface. High temperatures caused carbon diffuse surface, where atoms edges islands. Molecular dynamics and density functional theory calculations provide mechanistic insights into reaction steps. Science , this issue p. 1243

Ultrasmooth, highly spherical monocrystalline gold particles were prepared by a cyclic process of slow growth followed chemical etching, which selectively removes edges and vertices. The etching effectively makes the surface tension isotropic, so that spheres are favored under quasi-static conditions. It is scalable up to particle sizes 200 nm or more. resulting crystals display uniform scattering spectra consistent optical coupling at small separations, even showing Fano-like resonances in...

In the present work, a new way to obtain bimetallic nanoclusters of different structures and chemical compositions is proposed, which based on computer simulations. Collision processes between two metal clusters natures are simulated through molecular-dynamics simulations using many-body potentials. Diverse diffusion mechanisms can be observed, depending metals combined initial kinetic energies. The nanostructures we have found core-shell (Pt-Au), alloyed (Pd-Au), three-shell onionlike (Cu-Ag).

In this work we investigate the performance of several simulation techniques, i.e., Canonical Molecular Dynamics, Monte Carlo, and Optimized Multicanonical to study melting-like transitions Co/Au nanoalloys that are compared those pure Co Au clusters same size. A surprising enhancement in thermal stability core/shell Co13Au42 is observed both size shape. The novel property analyzed using energetic vibrational contributions throughout a detailed microscopic dynamic analysis.

We report the formation of Au/Co nanoparticles and their characterization by aberration (Cs) corrected scanning transmission electron microscopy (STEM). The were synthesized inert gas condensation, forming initially core-shell bimetallic crystals. However, after thermal treatment at normal atmospheric conditions, Co changed morphology into a fine layer perfect interface with gold. ordering zone rich in presents fcc arrangement matching gold lattice. atomic analysis on comparison STEM images...

In the present work new findings on structure of S–Au interface are presented. Theoretical calculations using a semiempirical potential, based density functional theory and bond-order Morse employed to simulate adsorption process in more realistic way. The simulation results reveal formation gold adatoms nanoparticle surface high disorder due strong bond. Experimental data were acquired by aberration (Cs) corrected scanning transmission electron microscopy (STEM) angle annular dark field...

We report the synthesis, structural characterization, and atomistic simulations of AgPd–Pt trimetallic (TM) nanoparticles. Two types structure were synthesized using a relatively facile chemical method: multiply twinned core–shell, hollow particles. The nanoparticles small in size, with an average diameter 11 nm narrow distribution, their characterization by aberration corrected scanning transmission electron microscopy allowed us to probe particles at level. In some nanoparticles, formation...

In this work we present an atomistic simulation study analyzing the effect of ligand molecules on morphology and crystalline structure monolayer protected gold nanoparticles (NPs). particular, focused Au NPs covered with alkyl thiolates (–SR), which form a strong covalent bond surface, amines (–NH2R), physisorb onto gold. The atomic interactions between head groups were represented by means recently developed bond-order potential [Olmos-Asar et al., Phys. Chem. Phys., 2011, 13, 6500]. We...

The scouting of alternative plasmonic materials able to enhance and extend the optical properties noble metal nanostructures is on rise. Aluminum endowed with a set interesting which turn it into an attractive material. Here we present electronic features different aluminum stemming from multilevel computational study. Molecular Dynamics (MD) simulations using reactive force field (ReaxFF), carefully validated Density Functional Theory (DFT), were employed mimic oxidation icosahedral...

A new semiempirical potential, based on density functional calculations and a bond-order Morse-like is developed to simulate the adsorption behavior of thiolate molecules non-planar gold surfaces, including relaxing effects, in more realistic way. The potential functions include as variables metal–molecule separation, vibrational frequencies, bending torsion angles between several pairs atom types coordination number both metal (Au) groups. was parameterized set molecular surface sites (i.e....

In the present work we show that synthesis of gold nanoparticles (NPs) could be performed by microwave-assisted technique without need adding any reducing agent. Only water and salt precursor are necessary to generate NPs under influence microwaves. The produced have been characterized state-of-art microscopy techniques, like high resolution transmission electron microscopy, scanning energy-dispersive x-ray. Theoretical calculations support experimental findings. It is expected opens routes...

In this work, the adsorption of very small rhenium clusters (2–13 atoms) supported on graphene was studied by high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM) in combination with density functional theory calculations.

The properties of palladium clusters, generated with the electrochemical scanning tunneling microscope, have been investigated both by experiments and computer simulations. clusters are found to be larger more stable if tip is moved further towards electrode surface in generation process. simulations suggest that consist a palladium–gold mixture, which than pure palladium. Dissolution occurs from edges rather layer layer.

The role that protecting molecules have on the way palladium atoms arrange themselves in nanoparticles prepared at room temperature was studied by analysis of aberration-corrected scanning transmission electron microscopy images and atomistic Langevin dynamics simulations. It found arrangement Pd is less ordered thiolate-protected than amine-protected ones. experimental theoretical data showed disorder ∼3 nm particles promoted strong S–Pd bond sulfide layer surrounds nanoparticles.

We report here that nanofluids of copper capped by graphene have an improved thermal conductivity compared to the Cu nanofluids, being up close 30 times higher for graphene-trilayered NPs.

We report on thermodynamic modeling and computer simulations the electrochemical generation of metallic bimetallic nanoparticles (NPs) by means quenched molecular dynamics (QMD). The present results suggest that spontaneous formation core-shell NPs depends several factors, i.e. size shape core, chemical composition system, under-/oversaturation conditions. Homo- heteroatomic prototypical systems were considered. former Au Pt. latter Ag(core)/Au(shell), Pt(core)/Au(shell), Au(core)/Ag(shell)...

Results of dynamical simulations collision-induced formation and properties bimetallic nanoparticles are presented analyzed. The analysis includes the effects collision energy impact parameter. For nonzero parameters, formed (in many cases Janus-type) rotating. rotating is decomposed into rotational vibrational components, structural these components Comparison made with case corresponding homoatomic systems, by same elemental composition.

We report a combined theoretical and experimental study on the growth mechanism of silver gold nanoparticles. introduce for first time grand-canonical Monte Carlo method to growth/dissolution steps nanoparticle mediated by seeds. In particular we found that small changes chemical potential, i.e. activity metal ions, produce significant size morphologies have very good agreements between simulated structures with those observed experimentally means scanning electron microscopy.