We measured Si L2,3 soft-X-ray emission spectra from Mo/Si multilayers annealed at 400°C. We showed that MoSi 2 was formed at the interface, and the thickness of the MoSi 2 interlayer increased with the annealing time. By an analysis of the soft-X-ray emission spectra and the patterns of small-angle X-ray diffraction, we estimated the thickness of the MoSi 2 interlayer and a diffusion coefficient between Mo and Si at 400°C as 1.1 (± 0.2) × 10-18 cm 2/ s . We showed that soft-X-ray emission spectroscopy is a useful tool for studying the thermal change of the buried interface nondestructively.
With the aim of studying the physicochemical interactions in metal-ceramic interfaces, we have investigated the Cu-MgO system. Two kinds of interfaces prepared at room temperature have been studied: interfaces during their formation (studied by X-ray photoelectron and Auger spectroscopies — XPS, AES) and buried interfaces (studied by electron-induced X-ray emission spectroscopy — EXES). Auger parameter results reveal a Cu(I) state for copper and point out, by comparison with the Cu-NaCl interface, that the oxidation comes from an interaction at the interface. EXES studies of the oxygen and copper valence densities of states evidence that the same kind of interaction exists at the interface between thick films of Cu and MgO and it does not exceed one interatomic distance.
An important parameter governing the sensitivity and accuracy of elemental analysis by electron energy-loss spectroscopy (EELS) or by X-ray emission spectroscopy is the signal/noise ratio of the characteristic signal.
Phosphorus is ubiquitous in biochemistry, found in the phosphate groups of nucleic acids and the energy-transferring system of adenine nucleotides (e.g. ATP). Kβ X-ray emission spectroscopy (XES) at phosphorus has...
Arsenoplatin-1 (AP-1), the prototype of a novel class of metallodrugs containing a PtAs(OH)2 core, was encapsulated within the apoferritin (AFt) nanocage. UV-Vis absorption spectroscopy and inductively coupled plasma-atomic emission spectroscopy measurements confirmed metallodrug encapsulation and allowed us to determine the average amount of AP-1 trapped inside the cage. The X-ray structure of AP-1-encapsulated AFt was solved at 1.50 Å. Diffraction data revealed that an AP-1 fragment coordinates the side chain of a His residue. The biological activity of AP-1-loaded AFt was comparatively tested on a few representative cancer and non-cancer cell lines. Even though the presence of the cage reduces the overall cytotoxicity of AP-1, it improves its selectivity towards cancer cells.
Phosphorus Kβ X-Ray emission spectroscopy detects non-covalent interactions of phosphate biomolecules in situ