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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

Mallett, B. P. P. ; Maršík, Premysl ; Yazdi-Rizi, M. ; Wolf, Th. ; Böhmer, A. E. ; Hardy, F. ; Meingast, C. ; Munzar, Dominik ; Bernhard, Christian

In: Physical Review Letters, 2015, vol. 115, no. 2, p. 027003

With infrared spectroscopy we investigated the spin-reorientation transition from an orthorhombic antiferromagnetic (o-AF) to a tetragonal AF (t-AF) phase and the reentrance of the o-AF phase in the superconducting state of underdoped Ba1−xKxFe2As2. In agreement with the predicted transition from a single-Q to a double-Q AF structure, we found that a distinct spin density wave develops in the...