2,835 research outputs found
Stability and electronic structure of the complex KPtCl structure-type hydrides
The stability and bonding of the ternary complex KPtCl structure
hydrides is discussed using first principles density functional calculations.
The cohesion is dominated by ionic contributions, but ligand field effects are
important, and are responsible for the 18-electron rule. Similarities to oxides
are discussed in terms of the electronic structure. However, phonon
calculations for SrRuH also show differences, particularly in the
polarizability of the RuH octahedra. Nevertheless, the yet to be made
compounds PbRuH and BeFeH are possible ferroelectrics. The
electronic structure and magnetic properties of the decomposition product,
FeBe are reported. Implications of the results for H storage are discussed
Hadron multiplicity induced by top quark decays at the LHC
The average charged hadron multiplicities induced by top quark decays are
calculated in pQCD at LHC energies. Different modes of top production are
considered. Proposed measurements can be used as an additional test of pQCD
calculations independent on a fragmentation model.Comment: 12 pages, 12 figures, to be published elsewher
Colour reconnections in Herwig++
We describe the implementation details of the colour reconnection model in
the event generator Herwig++. We study the impact on final-state observables in
detail and confirm the model idea from colour preconfinement on the basis of
studies within the cluster hadronization model. Moreover, we show that the
description of minimum bias and underlying event data at the LHC is improved
with this model and present results of a tune to available data.Comment: 19 pages, 21 figures, 2 tables. Matches with published versio
Karlstadter Positionspapier zum Schutz der Ackerwildkräuter. Erarbeitet von den Teilnehmerinnen und Teilnehmern der "Tagung zum Schutz der Ackerwildflora" am 25./26.6.2004 in Karlstadt am Main
Der Erhalt von Ackerwildkräutern, die historisch erst mit der Landbewirtschaftung in Mitteleuropa heimisch geworden sind, ist eine Kulturaufgabe, damit auch künftige Generationen die Arten- und Farbenvielfalt in der Kulturlandschaft erleben können
The Algorithm Steering and Trigger Decision mechanism of the ATLAS High Level Trigger
Given the extremely high output rate foreseen at LHC and the general-purpose
nature of ATLAS experiment, an efficient and flexible way to select events in
the High Level Trigger is needed. An extremely flexible solution is proposed
that allows for early rejection of unwanted events and an easily configurable
way to choose algorithms and to specify the criteria for trigger decisions. It
is implemented in the standard ATLAS object-oriented software framework,
Athena. The early rejection is achieved by breaking the decision process down
into sequential steps. The configuration of each step defines sequences of
algorithms which should be used to process the data, and 'trigger menus' that
define which physics signatures must be satisfied to continue on to the next
step, and ultimately to accept the event. A navigation system has been built on
top of the standard Athena transient store (StoreGate) to link the event data
together in a tree-like structure. This is fundamental to the seeding
mechanism, by which data from one step is presented to the next. The design
makes it straightforward to utilize existing off-line reconstruction data
classes and algorithms when they are suitableComment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 8 pages, PDF, PSN TUGT00
Intriguing Electrostatic Potential of CO: Negative Bond-ends and Positive Bond-cylindrical-surface
The strong electronegativity of O dictates that the ground state of singlet CO has positively charged C and negatively charged O, in agreement with ab initio charge analysis, but in disagreement with the dipole direction. Though this unusual phenomenon has been fairly studied, the study of electrostatic potential (EP) for noncovalent interactions of CO is essential for better understanding. Here we illustrate that both C and O atom-ends show negative EP (where the C end gives more negative EP), favoring positively charged species, whereas the cylindrical surface of the CO bond shows positive EP, favoring negatively charged ones. This is demonstrated from the interactions of CO with Na+, Cl-, H2O, CO and benzene. It can be explained by the quadrupole driven electrostatic nature of CO (like N2) with very weak dipole moment. The EP is properly described by the tripole model taking into account the electrostatic multipole moments, which has a large negative charge at a certain distance protruded from C, a large positive charge on C, and a small negative charge on O. We also discuss the EP of the first excited triplet COopen0
The Impact of Kaluza-Klein Excited W Boson on the Single Top at LHC and Comparison with other Models
We study the s-channel single top quark production at the LHC in the context
of extra dimension theories, including the Kaluza-Klein (KK) decomposition. It
is shown that the presence of the first KK excitation of gauge boson can
reduce the total cross section of s-channel single top production considerably
if () for () in
proton-proton collisions. Then the results will be compared with the impacts of
other beyond Standard Model (SM) theories on the cross section of single top
s-channel. The possibility of distinguishing different models via their effects
on the production cross section of the s-channel is discussed.Comment: 23 pages,6 figure
Exact Results for Kinetics of Catalytic Reactions
The kinetics of an irreversible catalytic reaction on substrate of arbitrary
dimension is examined. In the limit of infinitesimal reaction rate
(reaction-controlled limit), we solve the dimer-dimer surface reaction model
(or voter model) exactly in arbitrary dimension . The density of reactive
interfaces is found to exhibit a power law decay for and a slow
logarithmic decay in two dimensions. We discuss the relevance of these results
for the monomer-monomer surface reaction model.Comment: 4 pages, RevTeX, no figure
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