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Core-level shifts on Be(101̄0)

A high-resolution photoemission study of the Be (101̄0) surface, at a sample temperature of 100 K, is reported. Three surface-shifted Be 1s components are revealed having shifts of -700, -500, and -220 meV. These are interpreted as originating from the first, second, and third plus fourth atomic layers while the bulk signal originates from the fifth and deeper layers. The surface layer shift for t

The inner valence region of CO adsorbed on Pd(100)

The inner valence region of CO/Pd(100) p(2 square root 2* square root 2)R45 degrees has been studied by angular resolved photoemission at the Pd 4d Cooper minimum, and with resonant Auger spectroscopy at photon energies corresponding to the C 1s and O 1s X-ray absorption (XA) maxima of the unoccupied parts of the 2 pi *-Pd 4d hybrid (2 pi un). Previously unobserved inner valence states are reveale

As capping of MBE-grown compound semiconductors; novel opportunities to interface science and device fabrication

In situ condensation of an amorphous cap of the high vapour pressure element (i.e. As, Sb) has been found to provide effective protection of molecular beam epitaxy grown compound semiconductor surfaces against ambient contamination. Most work reported so far relates to arsenic-capped AlGaAs. Detailed investigation with surface sensitive structural (RHEED, LEED) and chemical (XPS) probes confirms t

Surface core-level shift of the Mo(110) surface

The surface core-level shift of the Mo(110) surface is determined from high-resolution photoemission measurements of the Mo 3d level. The 3d core-level binding energy of the surface atoms is found to be lowered by 333±10 meV relative to that of the bulk atoms. This result agrees well with semiempirical estimates and with the results of recent ab initio calculations. Decompositions of the spectra i

Observation of a low-binding-energy peak in the 2p core-level photoemission from oxidized Al(111)

High-resolution photoemission studies of oxidation of the Al(111) surface have been performed. The appearance of a component at lower binding energy than the metallic bulk Al emission in the Al 2p spectrum at oxygen exposures above ∼50 langmuir (1 L = 10-6 Torr s) is argued to be due to Al atoms which do not bond directly to oxygen atoms at the oxide-metal interface. Low-energy electron diffractio

Layer dependent core level binding energy shifts : Na, K, Rb and Cs on Al(111)

Layer resolved core level spectra are presented for Na, K, Rb and Cs films on Al(111). From the development of the spectra, it is possible to distinguish emission from alkali atoms at the interface, in the bulk, and at the surface of the adsorbed layers. The core level binding energy shifts are discussed in terms of adhesion and interface segregation energies. It is found experimentally that the A

Sm- and Yb-induced reconstructions of the Si(111) surface

Low-energy electron diffraction, scanning tunneling microscopy, and photoelectron spectroscopy results from the submonolayer Sm- and Yb-induced surface structures are presented. Several similar metal-induced surface reconstructions are found to exist for Yb and Sm on Si(111) for low submonolayer coverages: 3×2, 5×1, and 7×1. At higher submonolayer coverage, Yb induces a 2×1 reconstruction while Sm

Three surface-shifted core levels on Be(0001)

The results of a high resolution photoemission study of the Be(0001) surface carried out at temperatures between 100 and 450 K are reported. At 100 K, three distinctly shifted Be 1s levels, exhibiting shifts of -825, -570, and -265 meV, are revealed and interpreted to originate from the three outermost atomic layers. Identification of two subsurface core level shifts and a first layer surface shif

Polarisation-dependent X-ray absorption in high- and low-Tc Bi2Sr2Can-1CunO4+2n superconductors

Taking advantage of the linear polarisation of synchrotron radiation, the polarisation dependence of the O K and Cu L3 X-ray absorption edges has been compared for in situ cleaved Bi2Sr2CaCu2O8 and Bi2Sr2CuO6 single crystals. The X-ray absorption spectra were measured by means of total electron yield detection. The spectra show for both crystals that the lowest unoccupied Cu 3d and O 2p orbitals a

An Experimental Investigation on Inclined Negatively Buoyant Jets

An experimental study was performed to investigate the behavior of inclined negatively buoyant jets. Such jets arise when brine is discharged from desalination plants. A turbulent jet with a specific salinity was discharged through a circular nozzle at an angle to the horizontal into a tank with fresh water and the spatial evolution of the jet was recorded. Four different initial jet parameters we

Epitaxial silicide formation in the Mg/Si(111) system

The silicide formation has been studied in the Mg/Si(111) system by low energy electron diffraction (LEED) and photoelectron spectroscopy. It has been found that an epitaxial Mg2Si silicide is responsible for the ( 2 3√3 × 2 3√3)R30° reconstru system. The thickness of the silicide is limited due to the very low formation temperature for this silicide. The Fermi level is positioned 0.59 ± 0.06 eV a

Autoionization phenomena involving the 2p53d configuration of argonlike ions in ionic solids

The photon-induced Auger and photoelectron spectra of the argonlike ions Cl- (in NaCl), K+ (in KCl), Ca2+ (in CaCl2 and CaF2), and Sc3+ (in Sc2O3) have been measured in the vicinity of the L23 absorption edges of these ions. It is shown that at the 2p6→2p53d(4s) resonance a spectator structure appears in the L23M23M23 Auger spectra, which shifts to higher kinetic energies with increasing photon en

Alkali metal adsorption on Al(111)

The submonolayer adsorption of Na, K, Rb, and Cs on the Al(111) surface at 100 K and at room temperature is investigated by high resolution core level spectroscopy and low energy electron diffraction. It is found that the first alkali atoms on the surface adsorb at surface defects. At higher coverages, up to approximately one third of the maximum submonolayer coverage, alkali atoms adsorbed at def

The church building as an ecclesiological statement : An essay

The essay aims to set out some principles along which church buildings can be investigated as ecclesiological statements. It begins by considering the symbolic nature of all buildings and the general difficulties involved in interpreting them. Then it tackles the more specific difficulties involved in reading churches as ecclesiological statements. The last question considered is why not all churc

Modelling anaerobic co-digestion in Benchmark Simulation Model No. 2 : Parameter estimation, substrate characterisation and plant-wide integration

Anaerobic co-digestion is an emerging practice at wastewater treatment plants (WWTPs) to improve the energy balance and integrate waste management. Modelling of co-digestion in a plant-wide WWTP model is a powerful tool to assess the impact of co-substrate selection and dose strategy on digester performance and plant-wide effects. A feasible procedure to characterise and fractionate co-substrates

Mini Projects Solution for Energy, Wastewater and Water for the Gaza Strip, Palestine

Gaza has several water problems; limited fresh water supply, inefficient water use by the agricultural sector, high water demand, groundwater contamination, seawater intrusion and shortage of electricity. Water and electricity is the first priority for Gaza that will add significant positive values to the Palestinians living in blocked Gaza and easy operation and maintenance of their ongoing and e

Fabrication of topographically microstructured titanium silicide interface for advanced photonic applications

We present a widely scalable, high temperature post-growth annealing method for converting ultra-thin films of TiO2 grown by atomic layer deposition to topographically microstructured titanium silicide (TiSi). The photoemission electron microscopy results reveal that the transformation from TiO2 to TiSi at 950 °C proceeds via island formation. Inside the islands, TiO2 reduction and Si diffusion pl

Superresolution microscopy of the volume phase transition of pNIPAM microgels

Hierarchical polymer structures such as pNIPAM microgels have been extensively studied for their ability to undergo structural and physical transformations that can be controlled by external stimuli such as temperature, pH or solvent composition. However, a direct three-dimensional visualization of individual particles in-situ has so far been hindered by insufficient resolution, with optical micro

Climate Variability and Livelihood Diversification in Northern Ethiopia – A Case Study of Lasta and Beyeda Districts

This article examines smallholders’ perceptions of climate variability in two districts in Northern Ethiopia, and the diversification options pursued within and outside agriculture. Meteorological records corroborate smallholders’ belief that temperatures are increasing but do not support assertions that rainfall is decreasing. Farm-level adaptation mainly involves soil and water conservation meas

What role can Prezi play in students’ learning process?

This project offers an initial evaluation of using the online learning platform Prezi as a tool for increasing student learning within a MA unit in human geography. It does this by comparing the use of Prezi to four other learning activities conducted during the course. The aim of the project is to see whether the use of this technology became an end in itself, thereby distracting students and det