Showing papers by "Wolfgang Eberhardt published in 1993"
TL;DR: A method to determine the absorption coefficient near the onset of core-electron transitions for concentrated samples using fluorescence-yield (FY) detection is presented and is able to correct fully for saturation effects present in FY spectra of concentrated samples.
Abstract: A method to determine the absorption coefficient near the onset of core-electron transitions for concentrated samples using fluorescence-yield (FY) detection is presented. Measuring the FY signal for different experimental geometries, we are able to calculate the true absorption coefficient. Thus we are able to correct fully for saturation effects present in FY spectra of concentrated samples. The technique is demonstrated for Co and a buried layer of ${\mathrm{CoSi}}_{2}$.
195 citations
TL;DR: By spin resolved photoemission, exchange-split spin-polarized electronic states in a nonmagnetic material deposited on a magnetic substrate are detected and spectral polarization and intensity at the Fermi level display a periodicity correlated with the oscillations of the long range coupling between magnetic films separated by Cu(100) layers.
Abstract: By spin resolved photoemission we have detected exchange-split spin-polarized electronic states in a nonmagnetic material deposited on a magnetic substrate. Epitaxial Cu overlayers on fcc Co(100) exhibit sp symmetry electronic states which are spin polarized by the confining magnetic interface. These spin-polarized states can be observed up to a film thickness of at least 10 atomic layers. The spectral polarization and intensity at the Fermi level display a periodicity correlated with the oscillations of the long range coupling between magnetic films separated by Cu(100) layers.
123 citations
TL;DR: In this paper, a comparison of the electronic level structure of Cu−n clusters with the jellium model using photo-electron spectroscopy of metal cluster anions is presented, where the spectra are recorded at an energy resolution of 30 meV using photon energies of up to 6.4 eV.
Abstract: We present a comparison of the electronic level structure of Cu−n clusters with the jellium model using photoelectron spectroscopy of metal cluster anions. The spectra are recorded at an energy resolution of 30 meV using photon energies of up to 6.4 eV. We obtain a well resolved picture of the electronic structure of the 4s derived electronic states in the energy region between the localized 3d derived states and the highest occupied molecular orbital. The observed features can be assigned to the 1s, 1p, and 1d shells predicted by the jellium model if ellipsoidal distortions and effects like shake‐up processes, multiplet splittings and the s–d hybridization are taken into consideration.
97 citations
TL;DR: The main conclusions are that solid-state interactions play only a minor role in this new material, and electron correlation effects are predominantly intramolecular.
Abstract: We present a study of the electronic structure and electron correlation effects in gas-phase and solid C 60 clusters. Direct in situ comparison of C 1s absorption spectra taken in the gas phase with those from solid C 60 reveals a close similarity. This is also true for the shake-up satellites in the C 1s x-ray-photoelectron spectrum. The main conclusions are that solid-state interactions play only a minor role in this new material, and electron correlation effects are predominantly intramolecular
36 citations
TL;DR: In this paper, the surface of KNbO 3 single crystals was exposed to a variety of simple molecules (H 2, O 2, N 2, CO, CO 2, H 2 O, NH 3, NO 2, C 2 H 4, and (CH 3 ) 2 CO).
27 citations
TL;DR: In this paper, the decay of the 1σ−1u 1π3g core excited state in O2 was analyzed, where subsets of vibronic eigenfunctions could be selected.
25 citations
TL;DR: The exchange splitting of the 1σ g -1 3σ u shape resonance excitation of gas phase O 2 is determined and the pure core to 3σU bound state absorption spectrum is measured in partial secondary electron yield spectroscopy.
Abstract: We have determined the exchange splitting of the 1σ g -1 3σ u shape resonance excitation of gas phase O 2 , which cannot unambiguously be identified using conventional absorption spectroscopy. By identifying the electronic decay spectrum of the shape resonance excitation we could separately monitor the decay of the σ * shape resonance and the Rydberg states. Using this fingerprint method we measured the pure core to 3σ u bound state absorption spectrum in partial secondary electron yield spectroscopy
18 citations
TL;DR: In this paper, a single-scattering model was proposed to explain the near-edge structure in the X-ray absorption spectra of crystalline solids remarkably accurately, and the model was compared with experimental data for the K-edge absorption of fluorine in CaF 2, and of copper both in its f.c. c. form and as an epitaxial body centered tetragonal film.
6 citations
TL;DR: 3d-4d4d Auger spectra of Ce metal with the use of synchrotron radiation to excite the initial core hole are reported, enabling us to analyze the complex spectrum in terms of different contributions arising from various decay channels.
Abstract: We report 3d-4d4d Auger spectra of Ce metal with the use of synchrotron radiation to excite the initial core hole. By sweeping the excitation energy through the 3d\ensuremath{\rightarrow}4f threshold, it has been possible to excite different initial states selectively, enabling us to analyze the complex spectrum in terms of different contributions arising from various decay channels.
5 citations
TL;DR: The electronic structure of crystalline CoSi 2 produced by ion-beam synthesis has been studied and the unoccupied local Co d density of states (DOS) was determined via the Co L 3 nearedge absorption spectrum, measured in the fluorescence-yield mode.
Abstract: The electronic structure of crystalline CoSi 2 produced by ion-beam synthesis has been studied. Using fluorescence spectroscopies, we have taken advantage of the large photon penetration depth to obtain information from silicide layers, buried several hundred Angstroms deep in Si wafers, prepared by ion-beam synthesis. The unoccupied local Co d density of states (DOS) was determined via the Co L 3 nearedge absorption spectrum, measured in the fluorescence-yield mode. The occupied local Co d DOS was determined via the Co L 3 emission spectrum, excited both with photons and with high-energy electrons
5 citations
TL;DR: In this article, the growth of Pd on Fe(100) using LEED and Auger electron spectroscopy was studied and it was shown that Pd grows epitaxially and without interdiffusion up to 2 monolayers (ML) while layer by layer growth continues up to at least 5 ML.
TL;DR: In this paper, photoelectron spectroscopy was used to study the electronic level structure built from the delocalized s-orbitals of the atoms and an attempt was made to assign the observed bands to the electronic shells predicted by the jellium model.
Abstract: Copper cluster anions in the size range of 1-18 atoms are studied by photoelectron spectroscopy. Using photons of 5.0 eV energy the electronic level structure built from the delocalized s-orbitals of the atoms is revealed. An attempt is made to assign the observed bands to the electronic shells predicted by the jellium model. Even though the general behavior resembles the predictions of this model, the spectra are much more complicated reflecting the discrete atomic geometry of these particles.
01 Jan 1993
TL;DR: In this paper, the electronic structure and electron correlation effects of gas phase and solid C60 by C Is photoabsorption, photoelectron, and Auger spectroscopies were investigated.
Abstract: We have investigated the electronic structure and electron correlation effects of gas phase and solid C60 by C Is photoabsorption, photoelectron, and Auger spectroscopies. Direct in situ comparison between C Is absorption spectra taken in the gas phase and in the solid reveals a close similarity between the unoccupied levels of the two phases. The same is true for the shake up satellites in the C Is XPS spectrum. The satellite due to plasmon excitations, on the other hand, appears at about 6 eV higher binding energy in the gas phase than in the solid, due to the contribution of higher multipole moments. Solid state effects play only a minor role in this new material, and electron correlation effects are predominantly intra molecular.