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We present a line-shape analysis based on atomic single configuration Mn 3d6 multiplet calculations of core-level and valence-band spectroscopy data from metallic ferromagnetic Mn5Ge3. We show that atomic calculations can fit most of the spectral features measured in Mn 2p-3d x-ray absorption and circular dichroism, in Mn 2p and Mn 3s core-level photoemission, as well as for the delocalized electrons in valence-band photoemission. This indicates that, in spite of the metallic nature of the compound, atomic effects can play a relevant role to determine the physical properties of the Mn5Ge3 system.

The morphology and growth mechanism of nanostructurcd metals on semiconducting substrates determine crucially the electronic and physicochemical properties of these adsorption systems, In some cases. these properties are affected by modification of the interfacial geometry, induced by the metal adsorbate on the semiconducting substrate. Thus, in this work we investigate indium growth on the Si(111) root 3 x root 3 and Si(111)4 x I surfaces reconstructed by indium. The basic motivation of this study is to reveal how reconstruction of the silicon surface affects the growth mode and electronic properties of the indium overlayer. Therefore. the In/Si interface was mainly studied he Si 2p and In 4d photoemission spectra as well is he valence band measurements using synchrotron radiation, In addition, low-energy electron diffraction. Auger electron spectroscopy, thermal desorption spectroscopy, and electron energy loss spectroscopy were used to reveal the structure and adsorption states of the indium ticket-hate on the reconstructed silicon substrates. The results indicate that the initial In Si surf tee symmetry affects the growth mechanism of the indium overlayer. In particular, the Stransky-Krastanov mode holds for indium adsorption On the clean Si(111)7 x 7 and Si(111) root 3 x root 3 In-reconstructed surface. On the other hand, indium develops on the Si(111)4 x 1 In surface according to the Volmer Weber mechanism. The adsorbate approaches the metallic phase as the coverage approximates the monolayer irrespective of the substrate symmetry. Journal of Physical Chemistry C

In this study, we provide evidence of surface ferromagnetism in a thin metallic Mn:Ge(111) layer displaying a (root 3 x root 3)R30 degrees reconstruction. Magnetic circular dichroism effects are observed in remanence below the Curie temperature in both x-ray absorption spectroscopy and valence-band photoemission spectra, the latter indicating that spin-polarized states are present within 2 eV below the Fermi edge.

The absence of a clear signature of the Zhang-Rice singlet in the photoelectron valence band spectra of copper germanate raised the question of the stability of this state, induced by one-electron removal processes, in large-gap systems. Following Okada and Kotani [Phys. Rev. B 63, 045103 (2001)], we have performed a study of the O 1s resonant x-ray emission for CuGe1-xSixO3 (x=0, 0.05, and 0.1) single crystals as a function of temperature and polarization. Our experiment shows that the temperature, angle, and polarization dependence of the inelastic scattering emission detected at a 3.6 eV Raman shift in the O 1s resonant x-ray spectra can be unambiguously identified with the Zhang-Rice-singlet excitation.

We have investigated for the first time the orbital ordering in a three dimensional colossal magneto resistance manganite, namely La7/8Sr1/8MnO3, by applying soft x-ray linear dichroism (XLD) to the Mn L edge [1]. We found that the cooperative Jahn Teller distorted orthorhombic phase, which is present at a temperature of 240 K, is probably accompanied by a predominantly cross type (x2−z2)/(y2−z2) orbital ordering. This result is discussed in the light of previous results obtained by means of resonant x-ray scattering at the Mn K edge and different exchange interaction models. [1] K. Kuepper et al., J. Phys. Chem. B 109, 15667 (2005)

The charge transfer dynamics of an underdoped manganite is probed by resonant x-ray emission and Auger electron spectroscopies at the Mn L3 edge. The dispersion of peak positions, as the incident photon energy is tuned through the absorption threshold, gives direct information on the relaxation rate in terms of the core-hole lifetime and the localization behavior of the states involved. The charge transfer time is found to be around 0.45 fs, with a dependency on the final state d-band occupancy.

The charge transfer from Gd ions to C cage in endohedral Gd@C82 is probed by resonant photoemission spectroscopy. A careful data analysis shows that only one feature, ascribed to the 4f electron emission resonates across the Gd 4d?4f edge. The lack of the resonating spectral weight from the Gd 6s2 or 5d6s states, which in turn are detected in the resonant photoemission spectrum of metallic Gd and the binding energy of the 4f-1 resonating structure in valence band are the proof of an ionic picture (Gd3+) of the Gd-C bond. By fitting the integrated intensity of the 4f-1 structure with a Fano line shape, the time scale of the resonance process resulted to be of the order of 1.26×10-16 s.

We show that high-resolution real-time x-ray photoelectron spectroscopy can be used to determine hydrogen adsorption sites as a function of coverage on Rh?100?. The measurement of the surface core-level shifts does not suffer from the lack of direct sensitivity of other surface probes due to the low scattering cross section and high mobility of atomic hydrogen. At low temperatures ?70-140 K? and coverage (below 0.25 ML), we find that hydrogen adsorbs in fourfold hollow sites on Rh?100?, while at higher coverage the bridge site is preferred. Using Monte Carlo simulations, we unequivocally associate each surface component of the Rh 3d5/2 core level with a specific adsorption configuration. We obtain a value of 0.74±0.08 for the hydrogen initial sticking coefficient, in very good agreement with previous reports.

The Rh(110)-c(2x2)-CN phase has been examined by means of scanning tunneling microscopy (STM) and full dynamical low-energy electron diffraction (LEED). From STM large c(2x2) domains are observed. The detailed LEED-IV structural analysis indicates that CN is located in the grooves of the (110) surface, approximately atop second layer rhodium atoms. The CN molecules lie almost flat with their bond axes oriented perpendicular to the rhodium troughs. An outward relaxation of the first substrate interlayer distance and a strong buckling of the second Rh layer are induced by CN adsorption. Calculated and experimental intensity curves are in good agreement. An exhaustive set of other possible adsorption sites and configurations was tested and excluded on the basis of reliability-factor analysis.

We have investigated for the first time the orbital ordering in a three dimensional colossal magneto resistance manganite, namely La7/8Sr1/8MnO3, by applying soft x-ray linear dichroism (XLD) to the Mn L edge [1]. We found that the cooperative Jahn Teller distorted orthorhombic phase, which is present at a temperature of 240 K, is probably accompanied by a predominantly cross type (x2−z2)/(y2−z2) orbital ordering. This result is discussed in the light of previous results obtained by means of resonant x-ray scattering at the Mn K edge and different exchange interaction models. [1] K. Kuepper et al., J. Phys. Chem. B 109, 15667 (2005)

We measured the low energy excitation spectrum of α'-NaV (2)O(5) across its charge ordering and crystallographic phase transition with resonant inelastic x-ray scattering (RIXS) at the V L(3) edge. Exploiting the polarization dependence of the RIXS signal and the high resolution of the data, we reveal the excitation across the insulating gap at 1 eV and identify the excitations from occupied 3d(xy) bonding orbitals to unoccupied bonding 3d(xy) and 3d(yz)/3d(xz) orbitals. Furthermore we observe a progressive change of the electronic structure of α'-NaV (2)O(5) induced by soft x-ray irradiation, with the appearance of features characteristic of sodium deficient Na(x)V (2)O(5) (x 1).