Results 1 - 10 of 1824
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[en] Highlights: • Cationic chalcogen bonds between F3−nHnS+ cations (n = 0–2) and nitrogen bases are studied. • The interaction energies for these complexes vary between −6.17 and −53.16 kcal/mol. • Interaction energies of complexes with the sp-hybridized bases decrease in the FH2S+ > F2HS+ > F3S+. • All S⋯N interactions are characterized by a negative value of HBCP, except N2 complexes. The cationic chalcogen bond interactions between F3−nHnS+ (n = 0–2) and different nitrogen bases are studied at the MP2/aug-cc-pVTZ level of theory. The nitrogen bases include the sp bases NCH, NCF, NCCl, NCCN, NCCH3, NCOH and N2, and the sp3 bases NH3, NH2F, NH2Cl, NH2CN, NH2CH3 and NH2OH. The interaction energies for these complexes vary between −6.17 and −53.16 kcal/mol, while the S⋯N distances are in the range of 2.049–2.778 Å. Topological properties and natural bond orbital analyses are performed in order to provide the origin of the cationic chalcogen bonds.
[en] We report neutron-scattering studies on static magnetic orders and spin excitations in the Fe-based chalcogenide system Fe1+δSexTe1-x with different Fe and Se compositions. Short-range static magnetic order with an in-plane wave vector near the (0.5,0) (using the two-Fe unit cell), together with strong low-energy magnetic excitations is found in all nonsuperconducting samples for Se doping up to 45%. When the static order disappears and bulk superconductivity emerges, the spectral weight of the magnetic excitations shifts to the region of reciprocal space near the in-plane wave vector (0.5, 0.5), corresponding to 'collinear' spin correlations. Our results suggest that there is a strong correlation between superconductivity and the character of the magnetic order/fluctuations in this system. Excess Fe appears to be important for stabilizing the magnetic order that competes with superconductivity.
[en] Herein, the results of studies on the influence of γ - irradiation on electrophysical properties of terbium-doped alloys TbxSn1-xSe have been presented. It is assumed that terbium atoms are located in vacant places between the nodes of the crystal lattice within the irradiation of samples, and there occurs self-compensation with the occurrence of the Frenkel defect. This leads to a decrease in the concentration of charge carriers, however, the activation energy does not change
[en] Quaternary chalcogenide glasses based on sulphur and selenium Se80S18Tl2-xYbx (x = 0, 0.1, 0.2, 0.5 and 1) and Se65S10Ge15+xIn10-x (x = 0 and 5) were synthesized using the melt-quench technique. Formation of quaternary chalcogenide glasses was confirmed by Powder x-ray diffraction studies. Our differential scanning calorimetric studies on these glasses also are in good agreement with powder x-ray diffraction results. Thermo Gravimetric studies reveal the good thermal stability of these glasses. The IR transparency of Se80S18Tl1.5Yb0.5 extends throughout the range 3–25 μm and thus are good candidates for Infrared transmission applications. (paper)