2,699 research outputs found
Evidence of momentum dependent hybridization in Ce2Co0.8Si3.2
We studied the electronic structure of the Kondo lattice system Ce2Co0.8Si3.2
by angle-resolved photoemission spectroscopy (ARPES). The spectra obtained
below the coherence temperature consist of a Kondo resonance, its spin-orbit
partner and a number of dispersing bands. The quasiparticle weight related to
the Kondo peak depends strongly on Fermi vectors associated with bulk bands.
This indicates a highly anisotropic hybridization between conduction band and
4f electrons - V_{cf} in Ce2Co0.8Si3.2.Comment: 6 page
A framework for space-efficient string kernels
String kernels are typically used to compare genome-scale sequences whose
length makes alignment impractical, yet their computation is based on data
structures that are either space-inefficient, or incur large slowdowns. We show
that a number of exact string kernels, like the -mer kernel, the substrings
kernels, a number of length-weighted kernels, the minimal absent words kernel,
and kernels with Markovian corrections, can all be computed in time and
in bits of space in addition to the input, using just a
data structure on the Burrows-Wheeler transform of the
input strings, which takes time per element in its output. The same
bounds hold for a number of measures of compositional complexity based on
multiple value of , like the -mer profile and the -th order empirical
entropy, and for calibrating the value of using the data
Manufacturing improvements project and its impact on financial outcome
In response to changes in the external conditions of the oil and gas processing industry, the requirements for the equipment of the oil refinery are forced to change, which calls for the implementation of investment projects. The article considers the data on the implementation of the project for the reconstruction of the primary oil refinery, shows its main technical and economic indicators, examines the direction of the project's impact on the financial performance of the enterprise as a whole
Adsorption geometry and electronic structure of iron phthalocyanine on Ag surfaces: A LEED and photoelectron momentum mapping study
We present a comprehensive study of the adsorption behavior of iron
phthalocyanine on the low-index crystal faces of silver. By combining
measurements of the reciprocal space by means of photoelectron momentum mapping
and low energy electron diffraction, the real space adsorption geometries are
reconstructed. At monolayer coverage ordered superstructures exist on all
studied surfaces containing one molecule in the unit cell in case of Ag(100)
and Ag(111), and two molecules per unit cell for Ag(110). The azimuthal tilt
angle of the molecules against the high symmetry directions of the substrate is
derived from the photoelectron momentum maps. A comparative analysis of the
momentum patterns on the substrates with different symmetry indicates that both
constituents of the twofold degenerate FePc lowest unoccupied molecular orbital
are occupied by charge transfer from the substrate at the interface
Role of bulk and surface phonons in the decay of metal surface states
We present a comprehensive theoretical investigation of the electron-phonon
contribution to the lifetime broadening of the surface states on Cu(111) and
Ag(111), in comparison with high-resolution photoemission results. The
calculations, including electron and phonon states of the bulk and the surface,
resolve the relative importance of the Rayleigh mode, being dominant for the
lifetime at small hole binding energies. Including the electron-electron
interaction, the theoretical results are in excellent agreement with the
measured binding energy and temperature dependent lifetime broadening.Comment: 4 pages, 3 figure
Spin-orbit splitting of image states
We quantify the effect of the spin-orbit interaction on the Rydberg-like
series of image state electrons at the (111) and (001) surface of Ir, Pt and
Au. Using relativistic multiple-scattering methods we find Rashba-like
dispersions with Delta E(K)=gamma K with values of gamma for n=1 states in the
range 38-88 meV Angstrom. Extending the phase-accumulation model to include
spin-orbit scattering we find that the splittings vary like 1/(n+a)^3 where a
is the quantum defect and that they are related to the probability of spin-flip
scattering at the surface. The splittings should be observable experimentally
being larger in magnitude than some exchange-splittings that have been resolved
by inverse photoemission, and are comparable to linewidths from inelastic
lifetimes.Comment: 10 pages, 4 figure
Lifetimes of electrons in the Shockley surface state band of Ag(111)
We present a theoretical many-body analysis of the electron-electron (e-e)
inelastic damping rate of electron-like excitations in the Shockley
surface state band of Ag(111). It takes into account ab-initio band structures
for both bulk and surface states. is found to increase more rapidly as
a function of surface state energy E than previously reported, thus leading to
an improved agreement with experimental data
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