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X-ray absorption spectroscopy analysis: in situ, operando, in vivo
Iztok Arčon, 2020, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje)

Opis: X-ray absorption spectroscopy (XAS) is a powerful tool for characterisation of local structure and chemical state of selected elements in different new functional materials and biological or environmental samples. The XAS spectroscopy is based on extremely bright synchrotron radiation X-rays sources, which allow precise characterisation of bulk, nanostructured or highly diluted samples. With its two methods (XANES and EXAFS) it enables monitoring changes in valence states and local structures of constituent elements during chemical reactions under controlled reaction conditions, and it offers a possibility of a combination of X-ray spectroscopy and microscopy with sub-micron lateral resolution, crucial for analysis of biological samples on sub-cellular level. In this talk some typical examples of advanced XAS analysis will be presented.
Najdeno v: ključnih besedah
Ključne besede: X-ray absorption spectroscopy, EXAFS, XANES, in-situ, operando
Objavljeno: 17.10.2020; Ogledov: 2100; Prenosov: 0
.pdf Polno besedilo (68,21 KB)

Structure and population of complex ionic species in FeCl[sub]2 aqueous solution by X-ray absorption spectroscopy
Matjaž Valant, Iztok Arčon, Uroš Luin, 2022, izvirni znanstveni članek

Opis: Technologies for mass production require cheap and abundant materials such as ferrous chloride (FeCl2). The literature survey shows the lack of experimental studies to validate theoretical conclusions related to the population of ionic Fe-species in the aqueous FeCl2 solution. Here, we present an in situ X-ray absorption study of the structure of the ionic species in the FeCl2 aqueous solution at different concentrations (1–4 molL−1) and temperatures (25–80 ◦C). We found that at low temperature and low FeCl2 concentration, the octahedral first coordination sphere around Fe is occupied by one Cl ion at a distance of 2.33 (±0.02) Å and five water molecules at a distance of 2.095 (±0.005) Å. The structure of the ionic complex gradually changes with an increase in temperature and/or concentration. The apical water molecule is substituted by a chlorine ion to yield a neutral Fe[Cl2(H2O)4]0. The observed substitutional mechanism is facilitated by the presence of the intramolecular hydrogen bonds as well as entropic reasons. The transition from the single charged Fe[Cl(H2O)5]+ to the neutral Fe[Cl2(H2O)4]0 causes a significant drop in the solution conductivity, which well correlates with the existing conductivity models.
Najdeno v: ključnih besedah
Povzetek najdenega: ...FeCl2 solution. Here, we present an in situ X-ray absorption study of the structure of...
Ključne besede: structure, population, ionic species, aqueous ferrous chloride, in situ X-ray absorption spectroscopy
Objavljeno: 24.01.2022; Ogledov: 871; Prenosov: 26
URL Polno besedilo (0,00 KB)
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