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[en] We measured the nondipole parameters for the spin-orbit doublets Xe 4d_5/2 and Xe 4d_3/2 over a photon-energy range from 100 eV to 250 eV at beamline 8.0.1.3 of the Advanced Light Source at the Lawrence Berkeley National Laboratory. Significant nondipole effects are found at relatively low energies as a result of Cooper minima in dipole channels and interchannel coupling in quadrupole channels. Most importantly, sharp disagreement between experiment and theory, when otherwise excellent agreement was expected, has provided the first evidence of satellite two-electron quadrupole photoionization transitions, along with their crucial importance for a quantitatively accurate theory

[en] Full text: Measurements of electron, photon or ion yields as a function of photon energy in the region of inner-shell thresholds have long been known and used as a powerful probe of molecular spectroscopy, symmetry and photoionization dynamics. Anion spectroscopy constitutes a highly selective probe, yielding information unobtainable with absorption or electron spectroscopy, resulting in new experimental insights on resonant and non-resonant core-level processes. Here we present the cation and anion partial yields following photofragmentation of SO₂ near the sulphur L_2,3 ionization thresholds. The measurements were obtained using synchrotron radiation on undulator beamline 8.0.3 at the Advanced Light Source. Several cation fragments with the same mass/charge ratio could be observed by taking advantage of the ³⁴S isotope. Comparison is made to the absolute photoabsorption oscillator strengths of Feng et al. The S^-yield as a function of photon energy shows strong enhancement on the below threshold resonances with a broad weak peak above threshold corresponding to the doubly excited resonances

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[en] In order to determine the changes of the local structure around the Mn atoms in (Ga,Mn)As layers we have carried out an x-ray absorption spectroscopy experiment (EXAFS technique) in the samples grown by molecular beam epitaxy with and without annealing. The x-ray absorption is sensitive enough for determination of clusters formation and their crystalline structure changes in the consequence of annealing at the temperature of 600 ^oC. The qualitative and the quantitative analysis of EXAFS spectra gives unambiguously answer about the changes of the local structure around Mn atom from cubic to hexagonal (i.e. new phase formation, namely hexagonal inclusions of MnAs). (author)