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Resonant photoemission at core-level shake-up thresholds : Valence-band satellites in nickel

Three-hole satellites (3d7 final-state configuration) in the nickel valence-band photoelectron spectrum have been identified at 13 and 18 eV binding energy with use of synchrotron radiation from the MAX storage ring. The three-hole satellites show resonances at photon energies close to the threshold for excitation of 3p53d9 core-hole shake-up states. The 13-eV satellite also shows a resonance dire

Submicrometer-resolution photoelectron-spectroscopy at MAX Lab

The design of a photoemission microprobe beamline at the MAX laboratory is presented. The beamline will utilize the radiation from a 26 period undulator on the 550-MeV MAX storage ring. The beamline will be capable of providing about 1010 photons/s of monochromatized radiation (bandwidth better than 0.25 eV) in the energy range of 20 to 150 eV focused into a submicrometer focal spot. It will be us

Surface science at MAX-LAB

The 550 MeV storage ring at MAX-LAB provides synchrotron radiation for a large community of users. An important part of the scientific program is photoelectron spectroscopy studies of semiconductor and metal surfaces and interfaces. Here is a brief review of some of the experimental efforts obtained in this area. Results are shown for the Ge(100)2×1:As, Si(111):Au, Mo(110):Yb and Mo(110):Sm system

Soft x-ray emission spectroscopy using monochromatized synchrotron radiation (invited)

Soft x-ray emission spectroscopy is a common tool for the study of the electronic structure of molecules and solids. However, the interpretation of spectra is sometimes made difficult by overlaying lines due to satellite transitions or close-lying core holes. Also, irrelevant inner core transitions may accidentally fall in the wavelength region under study. These problems, which often arise for sp

Resonant behavior in soft x-ray fluorescence excited by monochromatized synchrotron radiation

Soft x-ray emission spectra of TiN, excited by monochromatized synchrotron radiation, have been recorded in a grazing-incidence spectrometer. The tunability of the excitation energy has allowed the pure N K and Ti LIII emission spectra to be isolated for the first time. A new type of resonance is observed in the Ti L emission spectrum, and interpreted as due to the decay of a quasiatomic intermedi

N-shell core-level widths for the elements W74 to Bi83

The Lorentzian lifetime widths of the 4d and 4f levels in the sixth-period elements W74 to Bi83 have been measured using photoelectron spectroscopy. A compilation of 4f-level widths from the literature is also made. The general trend of the 4f-level widths is well reproduced by McGuires calculations, although the absolute widths seem to be underestimated. The 4d5/2-level width shows a remarkable c

Core-excitoninduced desorption from MgO

Core-exciton-induced desorption of O and H from MgO(100) and MgO(111) has been observed using photon excitation energies spanning the O K edge. Electron-yield data from partially oxidized Mg implies that these states are localized in the near-surface region. O and H desorption results from the decay of different O core-exciton states as well as the states produced by interband transitions. The O e

A soft X-ray monochromator for the MAX synchrotron radiation facility

A high resolution soft X-ray monochromator for the 550 MeV MAX storage ring is described. The instrument combines a plane elliptical premirror collecting a large (10 mrad) horizontal angle of radiation and a modified version of the well-known SX-700 plane grating monochromator (PGM). The modification consists of changing the original ellipsoidal focussing mirror to a plane elliptical mirror. There

Design of a portable large spectral range grazing incidence instrument

A design of a small size grazing incidence instrument is presented, which offers large spectral range and high resolution without sacrificing luminosity. The instrument is particularly suited for use at synchrotron radiation sources since it can be conveniently attached to existing experiment chambers. The basic idea of the design is the use of fixed mounted gratings of diffent radii and groove de

Transition from bandlike to quasiatomic behavior in the N6,7O4,5O4,5 Auger spectra of iridium, platinum, and gold

The N6,7O4,5O4,5 Auger spectra of iridium, platinum, and gold have been measured. In conformity with the trends found in XVV spectra from the 3d- and 4d-series metals we find a change from bandlike toward quasiatomic behavior going from Ir to Au. The Auger spectrum from Ir is well described by a self-convolution of the valence band, thus showing a delocalized nature of the two-hole final state. Th

Surface and bulk core level binding energy shifts in PtAu alloys

The surface core level shift of the 4f 7 2 level in a Pt2%Au and a Pt15%Au alloy has been investigated using high resolution synchrotron radiation excited photoelectron spectroscopy. The bulk and surface components in the recorded spectra have been extracted using a curve fitting procedure. The chemical shifts and the bulk-to-surface intensity ratios are consistent with a strong enrichments of Au

Surface core level shift of the Be 1s level observed from a Be(0001) single crystal surface

We have used surface sensitive photoelectron spectroscopy to study the Be 1s core level from the Be(0001) single crystal surface. Two core peaks are observed, one from the bulk atoms, and the other from the first layer surface atoms. They are separated in binding energy by 0.50 eV, the surface peak being located at lower binding energy. This experimental surface core level shift (SCS) is compared

Resonant electron and ion emission and desorption mechanism in rare earth oxides

The resonant enhancement in photoelectron spectra at the 4d edges of rare earth atoms and metals is also found in yield spectra of desorbed ions from the surfaces of the oxides of Sm, Eu and Yb following the photon excitation. The analysis of the 4d → 4f resonance leads to a picture of an indirect mechanism of ion desorption which is mainly caused by the flux of energetic 4f photoelectrons from th

New observation of two-hole core-level satellites in copper, silver, and gold

The experimental core-level spectra for the noble metals Cu, Ag, and Au are shown to contain intrinsic satellite features. In the case of Ag, however, the identification is somewhat less certain than for the other two metals. The satellites are interpreted as being due to d-valence-electron shakeup processes. This view is supported by calculations of the multiplet splittings and also by calculatio

Resonant photoemission of oxidized Yb : Experiment and theory

The oxidation-induced valence change of Yb leads to a single 4f hole in the ground state. The creation of the 4f13 configuration which does not exist for any pure rare-earth metal makes it possible to analyze the 4d4f Fano resonance for a simple system experimentally as well as theoretically. Calculated Fano profiles for the 4f12 final-state multiplets are in good agreement with photoemission meas

Knowledge Base Combinations and Innovation Performance in Swedish Regions

The literature on geography of innovation suggests that innovation outcomes depend on a diversity of knowledge inputs, which can be captured with the differentiated knowledge base approach. While knowledge bases are distinct theoretical categories, existing studies stress that innovation often involves combinations of analytical, synthetic, and symbolic knowledge. It remains unclear, though, which