Université de Fribourg

Laboratory based XAS measurements, electron-induced double K-shell ionization of Sc, Cr and Cu : and, Chemical sensitivity of photoinduced Kʰβ hypersatelite transition in Cr compounds

Zeeshan, Faisal ; Dousse, Jean-Claude (Dir.)

Thèse de doctorat : Université de Fribourg, 2017 ; no. 2052.

The present PhD thesis includes three different projects which belong to the domain of inner-shell atomic physics and high energy resolution X-ray spectroscopy. The first project consists of a series of in-house measurements of the characteristic K and L X-ray absorption spectra (XAS) of several 3d, 4d and 5d transition metals. For this project the target chamber of the von Hamos curved crystal...

Université de Fribourg

Metallic contact between MoS2 and Ni via Au nanoglue

Shi, Xinying ; Posysaev, Sergei ; Huttula, Marko ; Pankratov, Vladimir ; Hoszowska, Joanna ; Dousse, Jean?Claude ; Zeeshan, Faisal ; Niu, Yuran ; Zakharov, Alexei ; Li, Taohai ; Miroshnichenko, Olga ; Zhang, Meng ; Wang, Xiao ; Huang, Zhongjia ; Saukko, Sami ; González, Diego López ; Dijken, Sebastiaan van ; Alatalo, Matti ; Cao, Wei

In: Small, 2018, vol. 14, no. 22, p. 1704526

A critical factor for electronics based on inorganic layered crystals stems from the electrical contact mode between the semiconducting crystals and the metal counterparts in the electric circuit. Here, a materials tailoring strategy via nanocomposite decoration is carried out to reach metallic contact between MoS2 matrix and transition metal nanoparticles. Nickel nanoparticles (NiNPs) are ...

Université de Fribourg

In situ high energy resolution off-resonant spectroscopy applied to a time-resolved study of single site Ta catalyst during oxidation

B³achucki, Wojciech ; Szlachetko, Jakub ; Kayser, Yves ; Dousse, Jean-Claude ; Hoszowska, Joanna ; Zeeshan, Faisal ; Sá, Jacinto

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...

Université de Fribourg

Distribution of aluminum over different T-sites in ferrierite zeolites studied with aluminum valence to core X-ray emission spectroscopy

Bohinc, R. ; Hoszowska, Joanna ; Dousse, Jean-Claude ; B³achucki, Wojciech Maria ; Zeeshan, Faisal ; Kayser, Yves ; Nachtegaal, Maarten ; Pinar, A. B. ; Bokhoven, Jeroen A. van

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...

Université de Fribourg

Theoretical and experimental determination of $L$-shell decay rates, line widths, and fluorescence yields in Ge

Guerra, Michel ; Sampaio, J. M. ; Madeira, T. I. ; Parente, F. ; Indelicato, Paul ; Marques, J. P. ; Santos, J. P. ; Hoszowska, Joanna ; Dousse, Jean-Claude ; Loperetti, L. ; Zeeshan, Faisal ; Müller, M. ; Unterumsberger, R. ; Beckhoff, Burkhard

In: Physical Review A, 2015, vol. 92, no. 2, p. 022507

Fluorescence yields (FYs) for the Ge L shell were determined by a theoretical and two experimental groups within the framework of the International Initiative on X-Ray Fundamental Parameters Collaboration. Calculations were performed using the Dirac-Fock method, including relativistic and QED corrections. The experimental value of the L3FYωL3 was determined at the Physikalisch-Technische...