In: Spectrochimica Acta Part B: Atomic Spectroscopy, 2017, vol. 136, p. 23–33
We review the high energy resolution off-resonant spectroscopy (HEROS) technique. HEROS probes the unoccupied electronic states of matter in a single-shot manner thanks to the combination of off-resonant excitation around atomic core states using wavelength dispersive X-ray detection setups. In this review we provide a general introduction to the field of X-ray spectroscopy together with the...
|
In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2017, vol. 411, no. Supplement C, p. 63–67
In the present work high energy resolution off-resonant X-ray spectroscopy (HEROS) was employed at a synchrotron to study a silica supported Ta(V) bisalkyl catalyst activated in hydrogen. The Ta Lα1 HEROS spectra were measured during oxidation of the starting complex and the relative species’ concentration was successfully retrieved as a function of time using the fingerprint HEROS spectra...
|
In: Physical Chemistry Chemical Physics, 2015, vol. 17, no. 28, p. 18262–18264
We report on the reactivity of grafted tantalum organometallic catalysts with molecular oxygen. The changes in the local Ta electronic structure were followed by in situ high-energy resolution off-resonant spectroscopy (HEROS). The results revealed agglomeration and formation of Ta dimers, which cannot be reversed. The process occurs independently of starting grafted complex.
|
In: Physical Review Letters, 2014, vol. 112, no. 17, p. 173003
X-ray emission spectra recorded in the off-resonant regime carry information on the density of unoccupied states. It is known that by employing the Kramers-Heisenberg formalism, the high energy resolution off-resonant spectroscopy (HEROS) is equivalent to the x-ray absorption spectroscopy (XAS) technique and provides the same electronic state information. Moreover, in the present Letter we...
|
In: Physical Chemistry Chemical Physics, 2017, vol. 19, no. 43, p. 29271–29277
The potential of valence to core Al X-ray emission spectroscopy to determine aluminum distribution in ferrierite zeolites was investigated. The recorded emission spectra of four samples prepared with different structure directing agents exhibit slight variations in the position of the main emission peak and the intensity of its low energy shoulder. Theoretical calculations indicate that an...
|
In: Physical Review A, 2009, vol. 80, no. 1, p. 012512
|
In: Physical Review A: atomic, molecular and optical physics, 2011, vol. 83, no. 2, p. 022708
The electron-induced L₃M two-step double ionization cross sections of metallic Pd were determined experimentally for incident electron beam energies ranging from the double ionization threshold up to 18 keV. The double L₃M ionization cross sections were derived from the intensity ratios (ILαM:ILα) of the resolved M satellites to the parent diagram lines. The sample was...
|
In: Journal of Analytical Atomic Spectrometry, 2014, vol. 27, no. 9, p. 1432–1438
In this work two synchrotron radiation-based depth-sensitive X-ray fluorescence techniques, grazing incidence X-ray fluorescence (GIXRF) and grazing emission X-ray fluorescence (GEXRF), are compared and their potential for non-destructive depth-profiling applications is investigated. The depth-profiling capabilities of the two methods are illustrated for five aluminum-implanted silicon wafers all...
|
In: Journal of Physics: Conference Series, 2010, vol. 212, no. 1, p. 012006
The photon energy dependence of the double K-shell ionization of light atoms is reported. Experimental double-to-single photoionization cross section ratios for Mg, Al, Si and Ca were obtained from measurements of high-resolution x-ray emission spectra. The double photoionization (DPI) cross-sections for K-shell hollow atom production are compared to convergent close-coupling calculations (CCC)...
|
In: Physical Review Letters, 2011, vol. 107, no. 5, p. 053001
xperimental evidence for the correlated two-electron one-photon transitions (1s⁻²→2s⁻¹2p⁻¹) following single-photon K-shell double ionization is reported. The double K-shell vacancy states in solid Mg, Al, and Si were produced by means of monochromatized synchrotron radiation, and the two-electron one-photon radiative transitions were observed by using a wavelength dispersive...
|
