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Spectroscopic investigations were performed on 68NH(4)H(2)PO(4).xLi(2)CO(3)(30-x)K(2)CO(3) and 68NH(4)H(2)PO(4).xNa(2)CO(3)(30-x)K(2)CO(3) (where x=5, 10, 15, 20 and 25) glasses containing 2 mol% Nd(2)O(3). Various spectroscopic parameters (Racah (E(1), E(2), E(3)), spin-orbit (xi(4f)) and configuration interaction (alpha)) are reported. Judd-Ofelt intensity parameters (Omega(2), Omega(4), Omega(6)) are calculated for Nd(3+) doped two mixed alkali phosphate glass matrices. From the magnitude of Judd-Ofelt parameters, covalency is studied as a function of x in the glass matrix. Using Judd-Ofelt intensity parameters, total radiative transition probabilities (A(T)), radiative lifetimes (tau(R)), branching ratios (beta) and integrated absorption cross sections (Sigma) have been computed for certain excited states of Nd(3+) in these mixed alkali phosphate glasses. Emission cross sections (sigma(P)) are calculated for the two transitions, (4)G(7/2)--(4)I(11/2) and (4)G(7/2)--(4)I(13/2) of Nd(3+) in these mixed alkali phosphate glasses. Optical band gaps (E(opt)) for direct and indirect transitions are reported.

EPR spectral investigations of some commonly available vegetables in south India, which are of global importance like Daucus carota (carrot), Cyamopsis tetragonoloba (cluster beans), Coccinia indica (little gourd) and Beta vulgaris (beet root) have been carried out. In all the vegetable samples a free radical corresponding to cellulose radical is observed. Almost all the samples under investigation exhibit Mn ions in different oxidation states. The temperature variation EPR studies are done and are discussed in view of the paramagnetic oxidation states. The radiation-induced defects have also been assessed by using the EPR spectra of such irradiated food products.

Ionoluminescence (IL), photoluminescence (PL) and thermoluminescence (TL) studies of YAlO3:Tb3+, Tm3+ (1 at %) single crystals are carried out using 100 MeV Si7+ ions for the fluence 3.91 × 1012 ions cm−2. IL peaks are recorded in the range 385–450, 493, 544, 585 and 624 nm in Tb3+- and 353, 459, 523, 651 and 763 nm in Tm3+-doped YAlO3 single crystals, respectively. PL studies also show similar characteristic emission peaks. The variation of IL intensity is studied in a YAlO3:Tb3+ crystal for a wide fluence range of 3.91 × 1012 –17.57 × 1012 ions cm−2. The IL intensity is found to be higher in lower ion fluences, and it decreases with the increase of ion fluence. Thermoluminescence (TL) studies are carried out for ion fluence– (3.91 × 1012 ions cm−2) and UV-exposed (05–60 min) single crystals. A single well-resolved glow peak at 242 °C, along with a shouldered peak at 272 °C, is recorded in the Tm3+-doped sample. In the Tb3+-doped samples, a well-resolved glow peak at 218 °C, along with a shouldered peak at 147 °C, is recorded at the lower temperature side. In the UV-exposed crystals, two glow peaks at 168 °C and 223 °C are recorded. The glow peaks are found to be shifted towards the lower temperature side with an increase in UV exposure time. Good linearity over a large span of UV exposure time and a single glow peak with a simple trap distribution are observed in YAlO3:Tb3+ single crystals, which makes them suitable as a dosimeter for UV-rays. The kinetic parameters (E, b, s) are estimated using the glow peak shape method for both ion and UV-exposed crystals, and the results are discussed in detail.

In this communication, we demonstrate that cadmium metasilicate nanobelts could be fabricated via a facile, eco-friendly, low cost hydrothermal treatment in the absence of surfactants and organic additives, followed by calcination. The monoclinic phase formation of the sample is described in detail by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and fourier transform infrared (FT-IR) studies. The field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) measurements of as-formed samples and samples calcined at 600 °C for 3 h indicate that the as-formed CdSiO3 sample consists of entangled nano-wire bundles with diameters ranging from 20 to 80 nm and lengths in the order of several micrometers. The calcined sample consists of nanobelts of slightly increased diameter and increased length compared to the as-formed samples. The selected area electron diffraction (SAED) and high resolution transmission electron microscopy (HRTEM) images reflect the polycrystalline nature of nanobelts. The probable mechanism for the formation of nanobelts is also discussed.

The effect of Li2SO4 on the electrical conductivity of Li2O- B2O3- P2O5 glass system prepared by melt quenching technique has been studied. Frequency and temperature dependent conductivity measurements have been carried out in the frequency range of 10 Hz to 10 MHz and a temperature range of 523 K-603 K respectively. Conductivity in these glasses is governed by the incorporation of lithium salt in the macromolecular structure. It exhibits Arrhenius behavior over the entire temperature range. Addition of Li2SO4 expands the glass network. Consequently the conductivity increases while activation energy decreases. Impedance spectra of these glasses show a single semicircle indicating one type of conduction. The nature of conductivity behavior observed can be explained using Almond-West type power law with a single exponent σ (ω) = σ (0) + A ωs. The power law exponent (s) decreases with temperature. Scaling behavior has also been carried out using the reduced plots of conductivity with frequency, which suggests the ion transport mechanism remains unaffected by temperature and composition.