A5058191756- Advanced Chemical Physics Studies
- Fullerene Chemistry and Applications
- Graphene research and applications
- Boron and Carbon Nanomaterials Research
- Molecular Junctions and Nanostructures
- nanoparticles nucleation surface interactions
- Carbon Nanotubes in Composites
- Advanced Physical and Chemical Molecular Interactions
- Catalytic Processes in Materials Science
- Spectroscopy and Quantum Chemical Studies
- Semiconductor materials and devices
- Machine Learning in Materials Science
- Protein Structure and Dynamics
- Chemical and Physical Properties of Materials
- X-ray Diffraction in Crystallography
- Material Dynamics and Properties
- Inorganic Fluorides and Related Compounds
- Catalysis and Oxidation Reactions
- Phase Equilibria and Thermodynamics
- Carbon Dioxide Capture Technologies
- Semiconductor materials and interfaces
- Organic Light-Emitting Diodes Research
- Solid-state spectroscopy and crystallography
- Quantum Dots Synthesis And Properties
- Surface and Thin Film Phenomena
École Polytechnique Fédérale de Lausanne
2013-2023
Institut de Physique
2021
Italian Institute of Technology
2016-2021
Charles Humbert 8
2021
IBM Research - Zurich
2000-2011
IBM (United States)
1991-2008
Novartis (Switzerland)
2005-2006
Novartis Institutes for BioMedical Research
2005
Universitat de Barcelona
2005
Institute of Theoretical Physics
1998
How thiols and disulfides bind to gold surfaces form self-assembled monolayers is a long-standing open question. In particular, determining the nature itself of anchor groups their interaction with metal priority issue, which has so far been approached only oversimplified models. We present ab initio calculations adsorption configurations (dissociative not) methanethiol dimethyl disulfide on Au(111) at low coverage, are based density functional theory using gradient-corrected...
Aluminas and their surface chemistry play a vital role in many areas of modern technology. The behavior adsorbed water is particularly important poorly understood. Simulations hydrated alpha-alumina (0001) surfaces with ab initio molecular dynamics elucidate aspects this problem, especially the complex dissociation related reactions. At low coverage, free energy profiles established that molecularly metastable dissociates readily, even absence defects, by kinetically preferred pathway....
We present extensive molecular-dynamics simulations of small gold particles N=100--900 atoms. use a many-body interatomic potential proven accuracy for surfaces. Structural properties are determined with various annealing strategies. Our results provide the first time microscopic description melting transition metal clusters, revealing in particular formation liquid skin as precursor effect N>350. The experimentally observed sharp decrease temperature decreasing size is recovered....
N , ′ -dioctyl-3,4,9,10-perylene tetracarboxylic diimide (PTCDI-C8H) thin films have been implemented into organic thin-film field-effect transistors. Mobilities up to 0.6 cm2 V−1 s−1 and current on/off ratios >105 were obtained. Linear regime mobilities typically half of those measured in the saturation regime. X-ray studies reflection mode suggest a spacing ∼20 Å for evaporated PTCDI-C8H, which is consistent with value ∼21±2 obtained from our simulations when an interdigitated...
We present the results of extensive computer simulations several sodium microclusters, using Car–Parrinello method (unified density-functional theory and molecular dynamics). Dynamical simulated annealing strategies are adopted in search for low-energy minima potential energy surface. A detailed analysis both structural electronic properties at temperatures 0–600 K range is carried out, which allows us first time to gain insight into ‘‘growth’’ pattern, extent validity (spherical,...
We show that new aspects of the physics microclusters can be investigated accurately with ab initio molecular dynamics. present results on a number properties ${\mathrm{Si}}_{N}$ aggregates ($N$ up to 10) at both zero and finite temperatures. The dynamical simulated annealing for ground state point complex growth sequence. Simulations temperatures existence two regimes, solidlike liquidlike, substantially different electronic structural properties.
Using the Car-Parrinello method, we have obtained unforeseen structures for low-lying isomers of ${\mathrm{Si}}_{45}$ and other midsized Si clusters. They are formed by two shells atoms, outer one (cage) being fullerenelike inner (core) consisting a few atoms saturating dangling bonds. These novel provide first time consistent interpretation available experimental data, including reactivity trends structural transition at size \ensuremath{\sim}25 atoms.
We report the first ab initio quasiparticle calculation in a real cluster ${\mathrm{Na}}_{4}$ within Hedin's $\mathrm{GW}$ approximation for valence electron self-energy. Our approach avoids summations over empty states, and also eliminates problem of residual interactions between periodic images. Self-energy corrections open local density gap by more than 2 eV; finite-size effects on screening are shown to play an important role. The absorption spectrum calculated including excitonic using...
We report the first parameter-free calculations of self-diffusion constants in silicon. have computed diffusion for defect-mediated mechanisms using local-density approximation combination with ab initio molecular-dynamics simulations and obtained constant concerted exchange mechanism from earlier results by Pandey Kaxiras. obtain range experimental values, self-interstitial dominating over contribution other mechanisms.
In December 1999, IBM announced the start of a five-year effort to build massively parallel computer, be applied study biomolecular phenomena such as protein folding. The project has two main goals: advance our understanding mechanisms behind folding via large-scale simulation, and explore novel ideas in machine architecture software. This should enable simulations that are orders magnitude larger than current technology permits. Major areas investigation include: how most effectively...
We present a more detailed account of our recently reported [Hass, K. C.; Schneider, W. F.; Curioni, A.; Andreoni, Science 1998, 282, 265] first-principles molecular dynamics investigation the static and dynamical behavior adsorbed H2O on α-Al2O3 (0001). Al-terminated surfaces with varying degrees coverage are modeled using large periodic supercells. A predicted relaxation clean surface agrees well previous density functional theory calculations. Both dissociative adsorption modes...
We report the results of an extensive structural study Na13, Mg13, Al13, and Si13 carried out with Car–Parrinello method. Several mostly unforeseen noncrystalline structures are discovered to characterize low portion potential energy surface. Crystalline shown either correspond high-energy local minima or be highly unstable. The low-energy pattern appears change significantly from one element other. Specific characteristics as well trends discussed.
The structural and electronic properties of the La@C(82) fullerene have been investigated by means Car-Parrinello method, which is based on local density approximation functional theory. topological arrangement C(82) cage was assumed to be a C(3v) symmetry isomer. Three configurations were considered, one with lanthanum atom at center cluster, it along threefold axis, low-symmetry, highly coordinated site. structure fully relaxed found that last these energetically preferred. In this...
We present the results of an ab initio molecular-dynamics study Si(111) surface at low temperatures. Our findings for equilibrium structure confirm Pandey (2\ifmmode\times\else\texttimes\fi{}1) chain model and are in very good agreement with both low-energy electron diffraction medium-energy ion-scattering data, showing particular a large buckling chains. describe dynamical path followed during reconstruction from ideal bulk-terminated surface, which is found to be unstable. The phonon...
Social permutation invariant coordinates are introduced describing the bond network around a given atom. They originate from largest eigenvalue and corresponding eigenvector of contact matrix, under identical atoms, bear clear signature an order-disorder transition. Once combined with ab initio metadynamics, these shown to be powerful tool for discovery low-energy isomers molecules nanoclusters as well blind exploration isomerization, association, dissociation reactions.
The electronic structure of Alq3 is investigated using density functional theory-based calculations, photoemission and near-edge x-ray absorption fine structure. distinct features the observed spectra are understood in terms contributions from different atoms molecular orbitals. Fingerprints bonding individual identified. These results meant to be a reference for monitoring chemical processes that may undergo during fabrication or degradation light-emitting devices, understanding effects...
We present a fully ab initio molecular dynamics study of the interaction cis-diamminedichloroplatinum(II) (cis-platin) with water and model for DNA adduct in water. Calculations use Car−Parrinello method, which is based on density-functional theory gradient-corrected functionals. Structural, electronic, dynamical properties are determined cis-platin monoaquo complex The mechanism first step hydrolysis, namely, Cl−H2O substitution reaction, characterized. free-energy barrier, calculated at...