After prolonged annealing of a Ru(0001) sample in ultrahigh vacuum superstructure with periodicity $\ensuremath{\sim}30\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$ was observed by scanning tunneling microscopy (STM). Using x-ray photoelectron spectroscopy it found that the surface is covered graphitic carbon. Auger electron shows between 1000 and $1400\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ carbon segregates to surface. STM images recorded after increasing temperatures display islands...

The dissociation of nitric oxide on a ruthenium(0001) surface was studied by scanning tunneling microscopy. distribution nitrogen atoms after the allowed identification "active sites" for this reaction, which are formed low-coordinated, top metal atomic steps. It is proposed that their activity caused local changes in electronic structure. structure steps determines whether they remain active or become deactivated oxygen atoms. results demonstrate complex manner catalytic reactivity catalyst...

The catalytic oxidation of carbon monoxide (CO) on a platinum (111) surface was studied by scanning tunneling microscopy. adsorbed oxygen atoms and CO molecules were imaged with atomic resolution, their reactions to dioxide (CO2) monitored as functions time. results allowed the formulation rate law that takes distribution reactants in separate domains into account. From temperature-dependent measurements, kinetic parameters obtained. Their values agree well data from macroscopic...

The structure of a single layer graphene on Ru(0001) has been studied using surface x-ray diffraction. A surprising superstructure containing 1250 carbon atoms determined, whereby $25\ifmmode\times\else\texttimes\fi{}25$ unit cells lie $23\ifmmode\times\else\texttimes\fi{}23$ Ru. Each supercell contains $2\ifmmode\times\else\texttimes\fi{}2$ crystallographically inequivalent subcells caused by corrugation. Strong intensity oscillations in the rods demonstrate that Ru substrate is also...

The interaction of oxygen with Al(111) was studied by scanning tunneling microscopy (STM). Chemisorbed and surface oxides can be distinguished in STM images, where for moderate tunnel currents independent the bias voltage former are imaged as depressions, while latter appear protrusions. An absolute coverage scale established counting O adatoms. initial sticking coefficient is determined to so=0.005. Upon chemisorption at 300 K adlayer characterized randomly distributed, immobile, individual...

Scanning-tunneling-microscopy observations on an Al(111) surface reveal that O adatoms at 300 K are practically immobile. Low-coverage overlayers formed by dissociative chemisorption of ${\mathrm{O}}_{2}$ consist essentially only single isolated atoms rather than pairs adjacent atoms. Hence, upon dissociation, least part the energy must be transformed into translational parallel to which causes two separate from each other 80 \AA{} before excess is dissipated. The lifetime these ``hot''...

The resolution of individual atoms in scanning-tunneling-microscopy (STM) images Al(111) is demonstrated. From results gap-width and energy-dependent measurements the corrugation observed STM cannot reflect electronic structure Al surface near ${E}_{F}$, as usually assumed for such images, but must be due to tip-surface interactions. On basis an investigation process tip preparation, elastic deformation frontmost end mediated by adhesive interactions proposed predominant factor...

The dissociation of ${\mathrm{O}}_{2}$ on a Pt(111) surface was studied by variable temperature scanning tunneling microscopy at 150--106 K. two oxygen atoms created the appear in pairs, with average distances lattice constants. Since thermal random walk sets only around 200 K, diffusion barrier 0.43 eV and preexponential factor ${10}^{\ensuremath{-}6.3}{\mathrm{cm}}^{2}{\mathrm{s}}^{\ensuremath{-}1}$, distribution 160 K evidences nonthermal processes during dissociation. It is concluded...

Epitaxial graphene on Ru(0001) was studied by means of large-scale density functional theory (DFT) calculations. The results agree well with scanning tunneling microscopy experiments. In contrast to the current understanding, we show that measured corrugation originates mainly from a geometric buckling sheet, induced alternating weak and strong chemical interactions Ru support. contact regions, charge transfer is evidenced opening considerable band gap in found.

The catalytic formation of water from adsorbed hydrogen and oxygen atoms on Pt(111) was studied with scanning tunneling microscopy high resolution electron energy loss spectroscopy. known complexity this reaction is explained by the strongly temperature dependent lifetime product ${\mathrm{H}}_{2}\mathrm{O}$ molecules surface. Below desorption reacts unreacted O adatoms to ${\mathrm{OH}}_{\mathrm{ad}}$, leading an autocatalytic process; at higher temperatures sequential addition H...

The structure of a single-layer graphene on Ru(0001) is compared with that hexagonal boron nitride nanomesh Ru(0001). Both are corrugated $s{p}^{2}$ hybridized networks and display $\ensuremath{\pi}$ band gap at the $\overline{\text{K}}$ point their $1\ifmmode\times\else\texttimes\fi{}1$ Brillouin zone. In contrast to $h\text{-BN}/\text{Ru}(0001)$, $g/\text{Ru}(0001)$ has distinct Fermi surface. Together measurements this indicates $0.1e$ per unit cell transferred from Ru substrate graphene....

The structure of the commensurate (23x23) phase graphene on Ru(0001) has been analyzed by quantitative low-energy electron diffraction (LEED)-I(V) analysis and density-functional theory calculations. I(V) uses Fourier components as fitting parameters to determine vertical corrugation lateral relaxation top Ru layers. Graphene is shown be strongly corrugated 1.5 A with a minimum C-Ru distance 2.1 A. Additionally, displacements C atoms significant buckling in underlying layers are observed,...

Scanning tunneling microscopy data revealed the atomic processes in propagating reaction fronts that occur catalytic oxidation of hydrogen on Pt(111). The were also characterized mesoscopic length scales with respect to their velocity and width. Simulations basis a reaction-diffusion model reproduce experimental findings qualitatively well. quantitative comparison reveals limitations this traditional approach modeling spatiotemporal pattern formation nonlinear dynamics.

OH species adsorbed on Pt(111) were studied in a combined investigation using scanning tunneling microscopy (STM) and high-resolution electron energy loss spectroscopy (HREELS). was formed by two different reactions, reaction of H2O with O, as an intermediate the O hydrogen to H2O. In both cases, ordered phases observed, (√3×√3)R30° (3×3) structure, for which models are proposed. Both structures have coverages 2/3, their formation is driven bond between adparticles; adsorption site most...

The dynamic behavior of N atoms adsorbed on a Ru(0001) surface was studied by scanning tunneling microscopy. formed dissociation NO molecules show an initial sharp concentration profile at atomic steps. Its decay followed as function time, providing quasicontinuum diffusion constant; the activation energy is 0.94 eV and prefactor $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}\phantom{\rule{0ex}{0ex}}{\mathrm{cm}}^{2}{\mathrm{s}}^{\ensuremath{-}1}$. constant determined also...

Using density functional theory (DFT), a detailed analysis of the energetic and electronic properties monolayer graphene on Ru(0001) was performed. Firstly, we demonstrate that corrugated (12×12)C/(11×11)Ru structure is an absolute minimum among smaller larger commensurabilities. Secondly, show reduced work function originates from charge depletion in skeleton states at bonded carbon atoms, contrast to assumed n-doping π states. We further propose higher-lying regions layer form array...

Silver's unique ability to selectively oxidize ethylene oxide under an oxygen atmosphere has long been known. Today it is the foundation of manufacturing. Yet, mechanism selective epoxide production unknown. Here we use a combination ultrahigh vacuum and in situ experimental methods along with theory show that only species shown produce oxide, so-called electrophilic appearing at 530.2 eV O 1s spectrum, adsorbed SO4. This adsorbate part 2D Ag/SO4 phase, where nonstoichiometric surface...

The epitaxial growth of graphene by chemical vapor deposition ethylene on a Ru(0001) surface was monitored high-temperature scanning tunneling microscopy. in situ data show that at low pressures and high temperatures the metal facets into large terraces, leading to much better ordered layers than resulting from known mode. Density functional theory calculations single terrace mode can be understood energetics graphene-metal interaction.

A path through a crowd Catalytic reactions on surfaces occur at pressures which the are completely covered with adsorbed molecules. It would seem that this arrangement interfere reactants encountering one another diffusion processes. Henß et al. used high-speed scanning tunneling microscopy to follow of oxygen atoms ruthenium surface was fully carbon monoxide (CO) molecules (see Perspective by Magnussen). Oxygen-atom unexpectedly fast. theoretical model revealed CO appears open pathways for...

The diffusive motion of O atoms adsorbed on Ru(0001) was observed the atomic scale by scanning tunneling microscopy with temporal resolution $\ensuremath{\approx}10\mathrm{ms}$ at room temperature. From statistical analysis changes atom configurations in sequences more than 1000 images, mean residence times oxygen neighborhood other were extracted. vary 1 order magnitude over distances three lattice constants, indicating necessity including lateral interaction modeling collective phenomena...