Publications by authors named "X Kozina"

We correct values and figures for the resolution of the spectrometer, as proposed in [Opt. Express25, 31840 (2017)10.1364/OE.

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Article Synopsis
  • The study investigates how adding 20 mol % tin fluoride (SnF) to cesium tin bromide (CsSnBr) affects its chemical and electronic properties using advanced X-ray photoelectron spectroscopy techniques.
  • Findings indicate that SnF improves coverage on titanium dioxide substrates and stabilizes tin, limiting unwanted chemical reactions that produce additional species.
  • Despite some variability in results, the research suggests that SnF alters the electronic structure by reducing the energy gap between the valence band maximum and the Fermi level, linked to changes in defect chemistry.
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A collimating polycapillary half lens, traditionally used in the medium and hard X-ray band, is operated at a photon energy of 36 eV for the first time. While the transmission still exceeds 50%, the measured and simulated spatial resolution and angular divergence approach 0.4 mm or less and at most 20 mrad, respectively.

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We present high-resolution near-edge X-ray absorption fine structure (NEXAFS) measurements at the P L edges, F K edge, C K edge, and Se M edges of the quasi-one-dimensional (1D) conductor and superconductor (TMTSF)PF. NEXAFS allows probing the donor and acceptor moieties separately; spectra were recorded between room temperature (RT) and 30 K at normal incidence. Spectra taken around RT were also studied as a function of the angle (θ) between the electric field of the X-ray beam and the 1D conducting direction.

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We have investigated the charge transfer mechanism in single crystals of DTBDT-TCNQ and DTBDT-F4TCNQ (where DTBDT is dithieno[2,3-d;2',3'-d'] benzo[1,2-b;4,5-b']dithiophene) using a combination of near-edge X-ray absorption spectroscopy (NEXAFS) and density functional theory calculations (DFT) including final state effects beyond the sudden state approximation. In particular, we find that a description that considers the partial screening of the electron-hole Coulomb correlation on a static level as well as the rearrangement of electronic density shows excellent agreement with experiment and allows to uncover the details of the charge transfer mechanism in DTBDT-TCNQ and DTBDT-F4 TCNQ, as well as a reinterpretation of previous NEXAFS data on pure TCNQ. Finally, we further show that almost the same quality of agreement between theoretical results and experiment is obtained by the much faster Z+1/2 approximation, where the core hole effects are simulated by replacing N or F with atomic number Z with the neighboring atom with atomic number Z+1/2.

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