Henrik Grönbeck

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Density functional theory is used to explore the structure of Au25(RS)18. The preferred structure consists of an icosahedral Au13 core protected by 6 RS-Au-RS-Au-RS units. The enhanced stability of the structure as an anion is found to originate from closure of an eight-electron shell for delocalized Au(6s) electrons. The evaluated XRD pattern and optical(More)
Synthesis, characterization, and functionalization of self-assembled, ligand-stabilized gold nanoparticles are long-standing issues in the chemistry of nanomaterials. Factors driving the thermodynamic stability of well documented discrete sizes are largely unknown. Herein, we provide a unified view of principles that underlie the stability of particles(More)
Density functional theory calculations are used to explore phosphine- and thiolate-protected gold nanoclusters, namely, Au(39)(PH(3))(14)Cl(6) and Au(38)(SCH(3))(24). For Au(38)(SCH(3))(24), a novel structural motif is predicted, consisting of ringlike (AuSCH(3))(4) units protecting a central Au(14) core. The calculated optical spectrum of this species(More)
A first-principles account of the observed limiting thickness of oxide films formed on aluminum during oxidizing conditions is presented. The results uncover enhanced bonding of oxygen to thin alumina films in contact with metallic aluminum that stems from charge transfer between a reconstructed oxide-metal interface and the adsorbed molecules. The(More)
The density functional theory is used to explore structural, energetic, vibrational, and optical properties of thiolated gold clusters (MeSAu)x with x = 2-12. Clusters up to (MeSAu)4 adopt Au-S ring conformations, and crownlike structures are formed for larger sizes. The clusters are essentially polymeric and show convergence in structural and energetic(More)
Density functional theory is used to investigate CO oxidation over an ultrathin MgO film supported on Ag(100). O(2) is found to be activated on MgO/Ag(100) whereas CO is only weakly bonded to the surface. These adsorption properties together with a low activation barrier render the MgO/Ag system an efficient catalyst for CO oxidation at low temperatures. As(More)
Stability parameters and dissolution behavior of engineered nanomaterials in aqueous systems are critical to assess their functionality and fate under environmental conditions. Using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, we investigated the stability of cubic MgO particles in water. MgO dissolution proceeding(More)
The density functional theory is used to explore alkylthiolates (RS) bonded to Au(111) and gold adatoms on Au(111). Adsorption of RS to adatoms in a structure characterized as an (RSAu)x polymer is strongly preferred over terrace adsorption. The energetic gain upon polymerization is large enough to drive the required Au(111) reconstruction. The results are(More)
Although modern catalytic converters significantly reduce pollution from automobile engines, a major amount of pollutants is still emitted just after " cold-start " , that is, until the catalytic converter warms up to its " ignition " temperature , at which the reaction rate rapidly switches from low to high conversion. There is thus substantial interest by(More)
Bioinspired structures are promising as improved catalysts for various redox reactions. One example is metal hangman-porphyrines (MHP), which recently have been suggested for oxygen reduction/evolution reaction (ORR/OER). The unique properties of the MHPs are attributed to both the hangman scaffold and the C6F5 side groups. Herein, the OER/ORR over various(More)