A5044607532- Advanced Chemical Physics Studies
- Catalytic Processes in Materials Science
- Atomic and Molecular Physics
- Nuclear physics research studies
- nanoparticles nucleation surface interactions
- Nanocluster Synthesis and Applications
- Molecular Junctions and Nanostructures
- Nuclear Physics and Applications
- Ion-surface interactions and analysis
- Mass Spectrometry Techniques and Applications
- Surface and Thin Film Phenomena
- Catalysis and Oxidation Reactions
- Advanced Materials Characterization Techniques
- Inorganic Chemistry and Materials
- Magnetic properties of thin films
- Atomic and Subatomic Physics Research
- Gold and Silver Nanoparticles Synthesis and Applications
- Advanced NMR Techniques and Applications
- Laser-induced spectroscopy and plasma
- Quantum Dots Synthesis And Properties
- Surface Chemistry and Catalysis
- Copper-based nanomaterials and applications
- Inorganic Fluorides and Related Compounds
- Fullerene Chemistry and Applications
- Theoretical and Computational Physics
KU Leuven
2015-2024
Teer Coatings (United Kingdom)
2021
Laboratoire de physique des Solides
2011-2020
Zdravstveni centar
2014
Fritz Haber Institute of the Max Planck Society
2009-2013
Clayton State University
2013
Institute of Physics
2005-2011
Jagiellonian University
2005-2011
Magneto Special Anodes (Netherlands)
2005-2009
Budapest University of Technology and Economics
2009
We investigated the stability of gold clusters doped with open 3d-shell atoms (Sc, Ti, V, Cr, Mn, Fe, Co, Ni). Steps, peaks, and odd-even staggering in mass abundance spectra upon photofragmentation provide evidence for enhanced specific cluster sizes. The observed magic numbers are explained terms size- dopant-dependent modifications effective mean-field potential within a phenomenological shell-model approach. Element-dependent 3d electron delocalization amplitudes related to dopant-atom structure.
Unambiguous values of the spin and magnetic moment $^{31}\mathrm{M}\mathrm{g}$ are obtained by combining results a hyperfine-structure measurement $\ensuremath{\beta}$-NMR measurement, both performed with an optically polarized ion beam. With measured nuclear $g$ factor $I=1/2$, $\ensuremath{\mu}(^{31}\mathrm{M}\mathrm{g})=\ensuremath{-}0.88355(15){\ensuremath{\mu}}_{N}$ is deduced. A revised level scheme ($Z=12$, $N=19$) ground state spin/parity ${I}^{\ensuremath{\pi}}=1/{2}^{+}$ presented,...
Unmasking the glow of silver clusters Small stabilized by organic materials or inorganic surfaces can exhibit bright photoluminescence, but origin this effect has been difficult to establish, in part because are heterogeneous and contain many larger inactive clusters. Grandjean et al. studied zeolites, using x-ray excited optical luminescence monitor only emissive structures (see Perspective Quintanilla Liz-Marzán). Aided theoretical calculations, they identified electronic states four-atom...
Starting from the gas phase, small clusters can be produced and deposited with huge flexibility regard to composition, materials choice cluster size. Despite many advances in experimental characterization, a detailed morphology of such is still lacking. Here we present an atomic scale observation as well dynamical behaviour ultrasmall germanium clusters. Using quantitative scanning transmission electron microscopy combination ab initio calculations, are able characterize transition between...
We report the experimental discovery of extremely stable metal-encapsulated superatom clusters a group IVA element: AlPb+10 and AlPb+12. Ab initio density functional geometry optimizations at B3LYP/LANL2DZ level result in perfect icosahedron with an exceptionally large HOMO-LUMO gap 3.1 eV for AlPb+12, related structure D(4d) symmetry AlPb+10, 2.6 eV. Their high stability is attributed to reinforcing influence most favorable closed-packed optimally filled electron shells.
A new dual-target dual-laser vaporization source for the production of binary metallic clusters is presented. Clusters type AunXm (X=Al, Fe, Co, Ni) were produced. Excellent control over mixing process was achieved by varying delay time between firing two lasers and their energy densities. Having identified these critical parameters, influence shown in detail AunAlm system. The bimetallic this due to spatial temporal overlap laser vaporized materials source.
Hyperfine structures and isotope shifts of strontium isotopes with A=78 to A=98 A=100 were measured by collinear fast beam laser spectroscopy. Nuclear spins, moments changes in mean square charge radii are extracted from the data. The spins most odd explained framework single particle model. compared predictions droplet model Hartree-Fock-plus-BCS calculations. For transitional regions below above N=50 shell closure, inclusion quadrupole zero point motion Droplet describes part observed...
Experimental and theoretical evidence for a "sigma aromatic" bimetallic cluster is presented. A mass spectrometric analysis of AuNZn+ (N = 2-44) photofragments shows Au5Zn+ to be very abundant, proving its high stability. Calculations predict that has planar geometry six valence s electrons occupying delocalized sigma-bonded molecular orbitals in manner similar aromatic organic compounds, except their nodal properties the plane. The sigma provide diamagnetic ring currents, suggesting aromatic.
General principles for designing stable highly symmetrical clusters are proposed. This approach takes advantage of both the extra stability cage aromaticity and good geometrical balance between outer endohedral atom. The applicability these design was confirmed by gas-phase experimental observations on group 14 element cages with Al's also is illustrated many literature examples diverse systems.
High-precision mass and charge radius measurements on $^{17--22}\mathrm{Ne}$, including the proton-halo candidate $^{17}\mathrm{Ne}$, have been performed with Penning trap spectrometry collinear laser spectroscopy. The $^{17}\mathrm{Ne}$ uncertainty is improved by factor 50, radii of $^{17--19}\mathrm{Ne}$ are determined for first time. fermionic molecular dynamics model explains pronounced changes in ground-state structure. It attributes large to an extended proton configuration ${s}^{2}$...
We present gas-phase infrared spectra for small silicon cluster cations possessing between 6 and 21 atoms. Infrared multiple photon dissociation (IR-MPD) of these clusters complexed with a xenon atom is employed to obtain their vibrational spectra. These give the first time experimental data capable distinguishing exact internal structures cations. By comparing theoretical predictions based on density functional theory (DFT), unambiguous structural assignments most Si(n)(+) in this size...
The geometry of cationic silicon clusters doped with vanadium, Si(n)V(+) (n=12-16), is investigated by using infrared multiple photon dissociation the corresponding rare gas complexes in combination ab initio calculations. It shown that are endohedral cages, and evidence provided Si(16)V(+) a fluxional system symmetric Frank-Kasper geometry.
The synthesis and characterization of LTA(Li)–Ag zeolites with water-responsive photoluminescence properties high external quantum efficiencies is described in this study.
The nonlinear absorption of Ag atomic clusters and nanoparticles dispersed in a transparent oxyfluoride glass host has been studied. as-prepared glass, containing 0.15 atom % Ag, shows an band the UV/violet attributed to presence amorphous nanoclusters with average size 1.2 nm. Upon heat treatment coalesce into larger that show surface plasmon visible. Open aperture z-scan experiments using 480 nm nanosecond laser pulses demonstrated nonsaturated saturated large indices for nanoparticles,...
Charge radii of all magnesium isotopes in the $sd$ shell have been measured, revealing evolution nuclear shape throughout two prominent regions assumed deformation centered on $^{24}\mathrm{Mg}$ and $^{32}\mathrm{Mg}$. A striking correspondence is found between charge radius neutron structure. The importance cluster configurations towards $N=8$ collectivity near $N=20$ discussed framework fermionic molecular dynamics model. These essential results made possible by first application...
The reactivity of small metallic clusters, nanoparticles composed a countable number atoms (typically up to ∼100 atoms), has attracted much attention due the fascinating properties these objects possess toward variety molecules. Cluster often is significantly different from homologous bulk, with gold as prototypical example. Bulk noblest all metals, whereas clusters react carbon monoxide, molecular oxygen, and hydrocarbons, among others. Furthermore, cluster strongly size composition...
The stability of gold clusters doped with transition metal atoms (Sc, Ti, Cr, Fe) is studied photofragmentation spectroscopy. recorded patterns depend on the kind and amount dopants. While for singly phenomenological electronic shell-model interpretations are suitable, limits this model encountered more complex systems containing multiple Density-functional theory calculations were carried out ${\mathrm{Au}}_{5}{X}^{+}$ $(X=\mathrm{Au},$ Sc, Fe). electron delocalization behavior suggested by...
We investigated the cluster-surface interaction of Au clusters deposited on MgO cubes and amorphous carbon, its influence morphology cluster. clusters, produced in a laser vaporization source, are with low energy carbon-coated microscope grids which first as substrates. Clusters carbon well studied by high-resolution electron microscopy (HREM). The have different morphologies for two surfaces, dilation lattice is also measured crystalline surface to perfectly accommodate lattice. Classical...
We present a study of the magnetic properties oxidized Co nanoparticles with an average grain size 3nm, embedded in amorphous Al2O3 matrix. These can be considered as imperfect Co-core CoO-shell systems. Magnetization measurements after field cooling show vertical shift hysteresis loop, while no exchange bias is observed. With simple model, we that there critical for hybrid ferromagnetic-antiferromagnetic particles, below which absent any ratio ferromagnetic and antiferromagnetic...