Synchrotron-based far-infrared spectroscopy of nickel tungstate

Monoclinic antiferromagnetic NiW ₄ was studied by far-infrared (30–600 cm−¹) absorption spectroscopy in the temperature range of 5–300 K using the synchrotron radiation from SOLEIL source. Two isomorphous CoWO₄ and ZnWO₄ tungstates were investigated for comparison. The phonon contributions in the far-infrared range of tungstates were interpreted using the first-principles spin-polarized linear combination of atomic orbital calculations. No contributions from magnetic excitations were found in NiWO₄ and CoWO₄ below their Neel temperatures down to 5 K

UV-VUV synchrotron radiation spectroscopy of NiWO₄

Photoluminescence and excitation spectra of microcrystalline and nanocrystalline nickel tungstate (NiWO₄) were measured using UV-VUV synchrotron radiation source. The origin of the bands is interpreted using comparative analysis with isostructural ZnWO₄ tungstate and based on the results of recent first-principles band structure calculations. The influence of the local atomic structure relaxation and of Ni²⁺ intra-ion d–d transitions on the photoluminescence band intensity are discussed

Phonon study of rhombohedral BS under high pressure

Raman spectra of rhombohedral boron monosulfide (r-BS) were measured under pressures up to 34 GPa at room temperature. No pressure-induced structural phase transition was observed, while strong pressure shift of Raman bands towards higher wavenumbers has been revealed. IR spectroscopy as a complementary technique has been used in order to completely describe the phonon modes of r-BS. All experimentally observed bands have been compared with theoretically calculated ones and modes assignment has been performed. r-BS enriched by 10B isotope was synthesized, and the effect of boron isotopic substitution on Raman spectra was observed and analyzed