Université de Fribourg

High energy resolution off-resonant spectroscopy: A review

B³achucki, Wojciech ; Hoszowska, Joanna ; Dousse, Jean-Claude ; Kayser, Yves ; Stachura, Regina ; Tyra³a, Krzysztof ; Wojtaszek, Klaudia ; Sá, Jacinto ; Szlachetko, Jakub

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...

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

Study of the reactivity of silica supported tantalum catalysts with oxygen followed by in situ HEROS

Błachucki, Wojciech ; Szlachetko, Jakub ; Kayser, Yves ; Dousse, Jean-Claude ; Hoszowska, Joanna ; Fernandes, Daniel L. A. ; Sá, Jacinto

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.

Université de Fribourg

Real time determination of the electronic structure of unstable reaction intermediates during Au₂O₃ Reduction

Szlachetko, Jakub ; Sá, Jacinto ; Nachtegaal, Maarten ; Hartfelder, Urs ; Dousse, Jean-Claude ; Hoszowska, Joanna ; Fernandes, Daniel Luis Abreu ; Shi, Hongqing ; Stampfl, Catherine

In: The Journal of Physical Chemistry Letters, 2014, vol. 5, no. 1, p. 80–84

Chemical reactions are always associated with electronic structure changes of the involved chemical species. Determining the electronic configuration of an atom allows probing its chemical state and gives understanding of the reaction pathways. However, often the reactions are too complex and too fast to be measured at in situ conditions due to slow and/or insensitive experimental techniques. A...