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Intermixing in the Na on Al(111) system

Ordered structures formed by Na adsorption on the Al(111) surface are investigated by high-resolution core-level spectroscopy. It is shown that, contrary to the common picture of alkali adsorption, two of the structures formed at room temperature consist of intermixed Na-Al layers. The results for the (3 ×)-rotated-30°structure are also consistent with intermixing although they do not provide any

Photoabsorption and the unoccupied partial density of states of chemisorbed molecules

The 1s to 2π* resonances have been studied for CO strongly chemisorbed on Ni(100) and weakly chemisorbed on Cu(100) using high resolution X-ray absorption spectroscopy. We show that the spectra can be consistently described in terms of the local density of unoccupied 2π* electron states with the Fermi level obtained from corresponding X-ray photoelectron spectra. The core hole is demonstrated to i

Soft x-ray emission studies of adsorbates

Soft x-ray emission spectroscopy is for the first time applied to surfaces and adsorbates. Surface sensitivity is achieved by employing synchrotron radiation in grazing incidence for the excitation. We present O K emission from adsorbed atomic oxygen on Ni(100) and Cu(100) and molecular CO on Ni(100). The observed spectral features correspond to the occupied 2p partial density of states of the ads

Synchrotron-radiation soft-x-ray photoemission study of lead on Bi2CaSr2Cu2O8

In this paper we present a study of the interaction of Pb with a clean single-crystal Bi2CaSr2Cu2O8 superconductor surface based on photoemission and low-energy electron diffraction (LEED). Deposition of Pb on a Bi2CaSr2Cu2O8 crystal kept at room temperature gives rise to the formation of metallic Bi and oxidized Pb at the interface. This behavior could not be observed when the crystal was kept at

Surface core-level shifts of the Al(100) and Al(111) surfaces

The surface core-level shifts of the Al(100) and Al(111) surfaces have been measured by high-resolution photoelectron spectroscopy. For the Al(100) surface we obtain a value of (-965) meV. This value is in excellent agreement with a recent ab initio calculation by Feibelman. The surface core-level shift of the Al(111) surface is found to be close to zero, and an upper limit of 15 meV is obtained.

Electronic and structural properties of the Cu - Bi2CaSr2Cu2O8 interface

The formation of the Cu-Bi2CaSr2Cu2O8 interface has been studied by photoelectron spectroscopy using synchrotron radiation. Photon energies in the range 20-1000 eV were utilized in order to probe both the valence band and to monitor chemical changes upon Cu deposition, as revealed by the core-level shifts. A strong chemical reaction between Bi2CaSr2Cu2O8 and Cu is manifested by the formation of me

Surface core-level shifts as a probe of the local overlayer structure : CO on Pd(100)

The bonding energies of the Pd 3d and the C 1s core levels have been studied for the p(2 S 2 × 2) R45°, p(3 s2 × S2) R45°, and p(4 S 2 × S 2) R45°structures of CO on Pd(100). Adsorption of CO shifts the Pd 3d surface emission to higher binding energies with the magnitude of the shift depending almost linearly on the number of Pd to CO bonds; the measured shift per bond is close to 0.5 eV. A direct

Outsourcing trust to the information infrastructure in schools : how search engines order knowledge in education practices

Purpose – This paper investigates the experiences of school teachers of supporting pupils and their apprehensions of how pupils search and assess information when search engines have become a technology of literacy in schools. By situating technologies of literacy as sociomaterial the purpose of this paper is to analyse and discuss these experiences and understandings in order to challenge dominan

Secondary photoelectron spectra of ionic solids as a function of the incident photon energy

Energy distributions of slow electrons (0-10 eV) emitted by thin layers of NaCl, KBr, CsBr, and CsI irradiated by monochromatic XUV photons with various energies in the interval of 50-300 eV are measured. The contributions of slow secondaries, hot secondaries and primary photoelectrons are obtained. It is shown that the higher the absorption coefficient for incident photons, the stronger the contr

Auger Spectra of K+ L23 Excitations in Potassium Halides

The L23M23M23 Auger spectra of K+ L23 excitation in potassium halides are measured using photon excitation with different energies in the region of the K+ L23 absorption edge (around 300 eV). It is shown that the screening of the two 3p holes caused by the collapsed 3d electron of the K+ L23 exciton leads to a considerable shift (by about (6÷7) eV) of the K+ L23M23M23 Auger bands to higher energie

Synchrotron-radiation-excited soft-x-ray-fluorescence studies of Cu and Zn : On the validity of the sudden approximation

The L23 x-ray-emission spectra of Cu and Zn have been recorded using tunable-synchrotron-radiation-excited fluorescence spectroscopy. The satellite structure was studied in detail by varying the excitation energy from threshold to several hundred eV above. Strong satellites are observed which can unambiguously be associated with the decay of multiply excited states. This disproves recent claims of

The nature of an upscale nature : Bro Hof Slott Golf Club and the political ecology of high-end golf

Political ecology, as a perspective for exploring power-permeated socio-ecological transformations, has to date rarely engaged with tourism. Neither has tourism theory, with some notable exceptions, engaged much with political ecology. In this article, I argue that the resultant lack of dialogue between these signifies a loss for political ecology and tourism theory alike, but also that current co