Spectroscopic studies and electrical conductivity behavior of γ-irradiated Li₂SO₄—Na₂SO₄mixed system

Abstract

The Li2S04-Na2S04 mixed system was prepared by the precipitation technique. Electron paramagnetic resonance (EPR) spectra of the y-irradiated Li2S04 -Na2S04 mixed system were measured at room temperature. Two types of centers, A and B, identified as SO; and SO,, respectively were studied. The SO; center is characterized by an intense isotropic signal with a g-value = 2.0029, while the SO; center appears as a weak and broad signal with a g-value of 2.02. Infrared spectra were recorded for unirradiated and y-irradiated samples. A decrease in the intensity of the IR spectra was observed after irradiation. The electrical conductivity, u, was measured for the Li2S04 -Na2S04 system before and after y-irradiation in the temperature range from 30 up to 430°C. A considerable decrease in the conductivity value accompanied by an increase in the activation energy was observed after gamma irradiation. The energy of formation of Frenkel defects was estimated to be 3.2eV. The current-voltage characteristics were measured at different temperatures in order to estimate the type of conduction in the samples. Isothermal annealing kinetics were investigated at different temperatures before and after y-irradiation.

Effect of gamma-irradiation on thermal decomposition kinetics, X-ray diffraction pattern and spectral properties of tris(1,2-diaminoethane)nickel(II)sulphate

“…Earlier studies on IR spectra of gamma-irradiated mixed sulphate systems have shown that the intensity of sulphate peaks decreased upon irradiation. The observed decrease in the IR intensity was attributed to the rupture of S-O bonds in SO 2−− 4 due to irradiation (11,12). Factors affecting the intensity of IR peak are dipole moment, concentration of molecules in the sample, transition probability, and so on.…”

“…(3,(8)(9)(10). infrared (IR) spectral studies indicated a decrease in the intensity of bands upon irradiation (3,(10)(11)(12). It has been reported that gamma irradiation produced marked changes in the ultraviolet (UV)-visible spectra of various glasses, polymers, antibiotics, and so on.…”

“…Literature survey revealed that unlike in other oxy anions, radiation damage in sulphate was studied mostly by electron spin resonance techniques (11,12,(17)(18)(19) except in a few cases. Radiation-induced decomposition of some transition metal sulphates and alkali metal sulphates was investigated by Johnson with a view to assessing the relative stability of sulphate ion on various lattices (20).…”

Thermoluminescence and photoluminescence characteristics of nanocrystalline LiNaSO4 : Eu phosphor

“…In the nanophosphor, the Eu 3+ ion, because of its higher oxidation state, would be surrounded by several negative ions such as O 2− , SO 2− 4 and OH − . On irradiation, these ions may break up into SO − 4 , SO − 3 , H + , O − and so on, as a result of rupture of S-O bonds and O-H bonds in the following manner [23,24]:…”

Pyroelectroluminescence in LiNaSO4 : Eu (particle size effect)

“…Osman et al [10] have reported the variation of the electrical conductivity of the unirradiated Li 2 SO 4 -Na 2 SO 4 system with temperature. It has been observed that in the temperature range 30-100˚C the conductivity decreases with increasing temperature.…”