Papers by Keyword: Infra-Red Spectroscopy

Abstract: Hydrogen is an impurity that is often present in LiXO₃ (X= Nb, Ta) single crystals and related materials. In this context, the diffusion of hydrogen is an important process because it may influence the overall conductivity of the material. We investigated the diffusional hydrogen uptake in LiNb_0.15Ta_0.85O₃ single crystals at 600 °C. For the experiments, O₂ is bubbled through liquid deuterated water (D₂O), which leads to a saturation of the gas atmosphere with D₂O that is incorporated into the crystal during isothermal annealing. The diffusivities of deuterium during uptake were determined by infra-red spectroscopy. We identified a fast process that can be associated with tracer diffusion and a second slower process with an almost three times lower diffusivity.

Abstract: The novel bicycloamino acid, 1−carboxyl−4−amino−2−aza−3−oxo−[2.2.2] bicyclooctane was synthesized and its physical characteristics have been compared to those predicted using quantum chemical calculations. The crystal structure of novel compound was determined by X-ray diffraction measurements at room temperature. Unit cell is monoclinic, with space group P 2₁/n (14) and a = 5.8587(6) Ǻ, b = 11.2454(16) Ǻ, c = 13.9723(16) Ǻ, β=97.840(6)°, Z = 2. Refinement was performed using all 1598 reflections with R = 0.4085 and wR = 0.6024. Theoretical calculation of full optimization and atomic net charge, and frontier orbital energies of the title compound was carried out at the B3LYP/6−31G(d,p) level. The NMR chemical shielding tensors and vibrational frequencies were calculated with B3LYP/6-311+G(2d, p)− level in which were close values and similar spectrum structures with experimental results and used to interpret the experimental measurements.

Abstract: Solid polymer electrolytes (SPEs) with poly (vinyl) chloride (PVC) doped with a fixed amount of ammonium trifluoro methane sulfonate (NH₄Tf) and with varying concentrations of ionic liquid butyltrimethyl ammonium bis (trifluoromethyl sulfonyl) imide (Bu₃MeNTf₂N) were synthesised via solution cast technique. PVC-NH₄Tf-Bu₃MeNTf₂N-based SPEs with 15 weight % Bu₃MeNTf₂N exhibit conductivity of 1.56 x 10^-4 Scm^-1 at room temperature. The ionic conductivity is attributed to the dissociation of NH₄Tf facilitated by Bu₃MeNTf₂N. Results of XRD indicate that the most amorphous film has the highest conductivity and this is corroborated by the results of DSC. FTIR spectra revealed that Bu₃MeNTf₂N has weak interaction suggesting that it acts mainly as a lubricant to facilitate polymer segmental motion.