Search results for " clusters"
showing 10 items of 1091 documents
"Table 14" of "Measurement of event shape and inclusive distributions at s**(1/2) = 130-GeV and 136-GeV."
1997
Oblateness distribution. Axis definition is from corrected charged plus neutral particles.
"Table 14" of "Tuning and test of fragmentation models based on identified particles and precision event shape data."
1996
Oblateness distribution. Corrected to final state particles.
"Table 8" of "Studies of quantum chromodynamics with the ALEPH detector"
1997
Charged particle Oblateness distribution.
Microscopic study of He2-SF6 trimers
2003
The He2-SF6 trimers, in their different He isotopic combinations, are studied in the framework of both the correlated Jastrow approach and the correlated hyperspherical harmonics (CHH) expansion method. The energetics and structure of the He-SF6 dimers are analyzed, and the existence of a characteristic rotational band in the excitation spectrum is discussed, as well as the isotopic differences. The binding energies and the spatial properties of the trimers, in their ground and lowest lying excited states, obtained by the Jastrow ansatz are in excellent agreement with the results of the converged CHH expansion. The introduction of the He-He correlation makes all trimers bound by largely sup…
Cooperative mechanism for anchoring highly polar molecules at an ionic surface
2009
Structure formation of the highly polar molecule cytosine on the (111) cleavage plane of calcium fluoride is investigated in ultrahigh vacuum using noncontact atomic force microscopy at room temperature. Molecules form well-defined trimer structures, covering the surface as homogeneously distributed stable structures. Density-functional theory calculations yield a diffusion barrier of about 0.5 eV for individual molecules suggesting that they are mobile at room temperature. Furthermore, it is predicted that the molecules can form trimers in a configuration allowing all molecules to attain their optimum adsorption position on the substrate. As the trimer geometry facilitates hydrogen bonding…
First-Principles Modelling of N-Doped Co3O4
2018
The project Nr. AP05131211 “First Principles Investigation on Catalytic Properties of N-doped Co3O4” is supported by the Ministry of Education and Science of the Republic of Kazakhstan within the framework of the grant funding for scientific and (or) scientific and technical research for 2018-2020. The authors thank T. Inerbaev and A. Popov for fruitful discussions and valuable suggestions. Yu.M. thanks M.Putnina for the technical assistance in preparation of the manuscript.
A Scanning Electron Microscope for Ultracold Atoms
2006
We propose a new technique for the detection of single atoms in ultracold quantum gases. The technique is based on scanning electron microscopy and employs the electron impact ionization of trapped atoms with a focussed electron probe. Subsequent detection of the resulting ions allows for the reconstruction of the atoms position. This technique is expected to achieve a much better spatial resolution compared to any optical detection method. In combination with the sensitivity to single atoms, it makes new in situ measurements of atomic correlations possible. The detection principle is also well suited for the addressing of individual sites in optical lattices.
Cooling and stabilization by collisions in a mixed ion–atom system
2012
In mixed systems of trapped ions and cold atoms, the ions and atoms can coexist at different temperatures. This is primarily due to their different trapping and cooling mechanisms. The key questions of how ions can cool collisionally with cold atoms and whether the combined system allows stable coexistence, need to be answered. Here we experimentally demonstrate that rubidium ions cool in contact with magneto-optically trapped rubidium atoms, contrary to the general experimental expectation of ion heating. The cooling process is explained theoretically and substantiated with numerical simulations, which include resonant charge exchange collisions. The mechanism of single collision swap cool…
2015
AbstractAtomic manipulation in the scanning tunnelling microscopy, conventionally a tool to build nanostructures one atom at a time, is here employed to enable the atomic-scale imaging of a model low-dimensional system. Specifically, we use low-temperature STM to investigate an ultra thin film (4 atomic layers) of potassium created by epitaxial growth on a graphite substrate. The STM images display an unexpected honeycomb feature, which corresponds to a real-space visualization of the Wigner-Seitz cells of the close-packed surface K atoms. Density functional simulations indicate that this behaviour arises from the elastic, tip-induced vertical manipulation of potassium atoms during imaging,…
Ab initio simulation of yttrium oxide nanocluster formation on fcc Fe lattice
2010
Using results of density functional theory (DFT) calculations the first attempt towards the understanding of Y2O3 particles formation in oxide dispersed strengthened (ODS) ferritic–martensitic steels was performed. The present work includes modeling of single defects (O impurity atom, Fe vacancy and Y substitute atom), interaction between substituted Y atoms, Y–Fe vacancy pairs and oxygen impurity atoms in the iron matrix. The calculations have showed the repulsive interaction between the two Y substitute atoms at any separation distances that might mean that the oxygen atoms or O atoms with vacancies are required to form binding between atoms in the yttrium oxide nanoclusters.