نتایج جستجو برای: MgO nanoclusters

تعداد نتایج: 10368  

2002
M. A. van Huis P. E. Mijnarends J. Kuriplach

Quantum confinement of positrons in nanoclusters offers the opportunity to obtain detailed information on the electronic structure of nanoclusters by application of positron annihilation spectroscopy techniques. In this work, positron confinement is investigated in lithium nanoclusters embedded in monocrystalline MgO. These nanoclusters were created by means of ion implantation and subsequent a...

Journal: :physical chemistry research 2015
afshan mohajeri akbar omidvar

magnesium oxide nanoclusters have attracted much attention due to their potential applications to catalysis and novel optoelectronic materials. in the present study, we have studied the electronic and magnetic properties of the stoichiometric magnesium oxide nanoclusters (mgo)n  for n = 2-20. although the binding energy increases with the size of the cluster, it  reaches the asymptotic limit of...

2008
Olli H. Pakarinen Clemens Barth Adam S. Foster Claude R. Henry

A quantitative comparison between experiment and theory is given for the constant height mode imaging of metal nanoclusters in dynamic scanning force microscopy. We explain the fundamental mechanisms in the contrast formation with the help of the system Pd/MgO 001 . The comparison shows that the shape and size of nanoclusters are precisely imaged due to the sharpness of the tip’s last nanometer...

Journal: :Physical review letters 2008
Bokwon Yoon Uzi Landman

Electric field control of the structure, dimensionality, and reactivity of gold nanoclusters (Au*(20)) deposited on MgO films of various thicknesses supported on Ag(100) are introduced and studied using first-principles electronic structure calculations. Field-controlled interfacial charging and field-induced dimensionality crossover are predicted. For a field E(z)=1 V/nm, an optimal planar Au(...

Journal: :Physical chemistry chemical physics : PCCP 2015
Ichraf Oueslati Boutheïna Kerkeni Stefan T Bromley

We study nanoclusters of Mg-rich olivine and pyroxene (having (MgO)6(SiO2)3 and (MgO)4(SiO2)4 compositions) with respect to their reactivity towards hydrogen atoms, using density functional calculations. Ultrasmall silicate particles are fundamental intermediates in cosmic dust grain formation and processing, and are thought to make up a significant mass fraction of the grain population. Due to...

Journal: :Journal of the American Chemical Society 2009
Chris Harding Vahideh Habibpour Sebastian Kunz Adrian Nam-Su Farnbacher Ueli Heiz Bokwon Yoon Uzi Landman

Control and tunability of the catalytic oxidation of CO by gold clusters deposited on MgO surfaces grown on molybdenum, Mo(100), to various thicknesses are explored through temperature-programmed reaction measurements on mass-selected 20-atom gold clusters and via first-principles density functional theory calculations. Au(20) was chosen because in the gas phase it is characterized as an extrao...

Magnesium oxide nanoclusters have attracted much attention due to their potential applications to catalysis and novel optoelectronic materials. In the present study, we have studied the electronic and magnetic properties of the stoichiometric magnesium oxide nanoclusters (MgO)n  for n = 2-20. Although the binding energy increases with the size of the cluster, it  re...

2007
Uzi Landman Bokwon Yoon Chun Zhang Ueli Heiz Matthias Arenz

Focusing on size-selected gold clusters consisting of up to 20 atoms, that is, in the size regime where properties cannot be obtained from those of the bulk material through scaling considerations, we discuss the current state of understanding pertaining to various factors that control the reactivity and catalytic activity of such nanostructures, using the CO oxidation reaction catalyzed by the...

Journal: :Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 2004

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