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...
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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...
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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...
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In: Physical Review A, 2010, vol. 82, no. 6, p. 063408
Single-photon double K-shell ionization of low-Z neutral atoms in the range 12⩽Z⩽23 is investigated. The experimental method was based on measurements of the high- resolution Kαh hypersatellite x-ray spectra following the radiative decay of the K-shell double-vacancy states excited by monochromatic synchrotron radiation. The photon energy dependence of the double K-shell ionization was...
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In: Scientific Reports, 2016, vol. 6, p. 33292
X-ray techniques have evolved over decades to become highly refined tools for a broad range of investigations. Importantly, these approaches rely on X-ray measurements that depend linearly on the number of incident X-ray photons. The advent of X-ray free electron lasers (XFELs) is opening the ability to reach extremely high photon numbers within ultrashort X-ray pulse durations and is leading...
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In: Journal of Physics: Conference Series, 2015, vol. 635, no. 10, p. 102009
We report on nonlinear interaction of solid Fe with intense femtosecond hard x-ray free-electron laser (XFEL) pulses. The experiment was performed at the CXI end- station of the Linac Coherent Light Source (LCLS) by means of high- resolution x-ray emission spectroscopy. The focused x-ray beam provided extreme fluence of ~10⁵ photons/Ų. Two-photon absorption leading to K-shell hollow atom...
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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.
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In: Journal of Analytical Atomic Spectrometry, 2015, p. -
Depth-profiling measurements by means of synchrotron radiation based grazing XRF techniques, i.e., grazing emission X-ray fluorescence (GEXRF) and grazing incidence X-ray fluorescence (GIXRF), present a promising approach for the non-destructive, sub-nanometer scale precision characterization of ultra shallow ion-implantations. The nanometer resolution is of importance with respect to actual...
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In: Spectrochimica Acta Part B: Atomic Spectroscopy, 2014, vol. 88, p. 136-149
The grazing emission X-ray fluorescence (GEXRF) technique was applied to the analysis of different Al films, with nominal thicknesses in the range of 1 nm to 150 nm, on Si wafers. In GEXRF the sample volume from which the fluorescence intensity is detected is restricted to a near-surface region whose thickness can be tuned by varying the observation angle. This is possible because of the...
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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...
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