Stability and spectroscopic properties of singly and doubly charged anions

Using density functional theory and hybrid B3LYP exchange-correlation energy functional we have studied the structure, stability, and spectroscopic properties of singly and doubly charged anions composed of simple metal atoms (Na, Mg, Al) decorated with halogens such as Cl and pseudohalogens such as CN. Since pseudohalogens mimic the chemistry of halogen atoms, our objective is to see if pseudohalogens can also form superhalogens much as halogens do and if the critical size for a doubly charged anion depends upon the ligand. The electron affinities of MCl(n) (M = Na, Mg, Al) exceed the value of Cl for n ≥ (k + 1), where k is the normal valence of the metal atom. However, for M(CN)(n) complexes this is only true when n = k + 1. In addition, while the electron affinities and vertical detachment energies of MCl(n) complexes are close to each other, they are markedly different when Cl is replaced by pseudohalogen, CN. The origin of these anomalous results is found to be due to the large binding energy of cyanogen, (NCCN) molecule. Because of the tendency of CN molecules to dimerize, the ground state geometries of the neutral and anionic M(CN)(n) complexes are very different when their number exceed the normal valence of the metal atom. While our calculations support the conclusion of Skurski and co-workers that pseudohalogens can form the building blocks of superhalogens, we show that there is a limitation on the number of CN moieties where this is true. Equally important, we find large differences between the ground state geometries of the neutral and anionic M(CN)(n) complexes for n ≥ (k + 2) which could play an important role in interpreting future experimental data on M(CN)(n) complexes. This is because the electron affinity defined as the energy difference between the ground states of the anion and neutral can be very different from the adiabatic detachment energy defined as the energy difference between the ground state of the anion and its structurally similar neutral isomer.     

Study of nucleon-nucleon and alphanucleon elastic scattering by the Manning-Rosen potential

Although often used in molecular dynamics, in this work the Manning–Rosen potential is parameterized to compute the scattering phase shifts for the nucleon–nucleon and the alpha-nucleon systems by exploiting the standard phase function method. We obtain excellent agreement in phase shifts with the more sophisticated calculations up to partial waves ${\ell }=2.$     

Solid-state fermentation of new substrates for production of cellulase and other biopolymer-hydrolyzing enzymes

Applied Biochemistry and Biotechnology -     

Organophosphinic,phosphonic acids and their binary mixtures as extractants for molybdenum(VI) and uranium(VI) from aqueous HCl media

Extraction studies of uranium(VI) and molybdenum(VI) with organophosphoric, phosphinic acid and its thiosubstituted derivatives have been carried out from 0.1–1.0M HCl solutions. The extracted species are proposed to be UO₂R₂ and MoO₂ CIR on the basis of slope analysis for uranium(VI) and molybdenum(VI), respectively. The extraction efficiencies of PC-88A, Cyanex 272, Cyanex 301 and Cyanex 302 in the extraction of molybdenum(VI) and uranium(VI) are compared. Synergistic effects have been studied with binary mixtures of extractants. Separation of molybdenum(VI) from uranium(VI) is feasible by Cyanex 301 from 1M HCl, the separation factor log being 2.3.     

Broad range frequency – temperature response of Ba2Zn2Fe12O22

Ba₂Zn₂Fe₁₂O₂₂ was synthesized by solid state reaction technique. The temperature and frequency dependent electrical properties and complex impedance spectroscopy were analysed. Complex modulus formalism shows the existence of high resistance and small capacitance of the material for the short range relaxation. The presence of non-Debye type relaxation is revealed from Nyquist plots and enabled to separate the contribution from bulk and grain boundary effect in the material. Further, the ac electrical conductivity of the material was well agreed with the Jonscher's universal power law.     

Studies of structure,dielectric and conduction mechanism of Bi3+/Yb3+ modified BaTiO3

The present communication aims at the study of the structural, dielectric, electrical and conduction properties of Bi³⁺/Yb³⁺ substituted BaTiO₃ with a chemical composition of Ba_0.5Bi_0.5Yb_0.5Ti_0.5O₃. The modified BaTiO₃, could be synthesized by a solid state reaction technique. The X-ray diffraction data and pattern revealed the formation of the above compound with tetragonal crystal system. The material's molecular structure (Ba–Ti–O bond, O–Ti–O stretching-mode, metal-oxygen bond, optical band gap, and so on) was determined using room temperature Fourier transform infrared (FTIR) and UV–visible spectroscopic spectra. Detailed investigations of the material's electrical (dielectric/leakage current and impedance) behavior over a wide temperature (25⁰C–500⁰C) and frequency (1 kHz–1000 kHz) range revealed the presence of capacitive, resistive, and conductive mechanisms. On the investigation of the polarization-electric field (P-E) hysteresis loop on multiple substitution, the change of ferroelectric polarization (spontaneous and residual) and storage density of BaTiO₃ was observed. Defect chemistry of the modified barium compound has been discussed in the details.     

Organically‐Templated Zinc and Thorium Sulfates with Chain and Layered Structures

Amine‐templated zinc sulfates of the formulae, [Zn(SO₄)(H₂O)₂(C₁₀N₂H₈)] ( I ) and [C₃N₂H₁₂][Zn(SO₄)] ( II ) both with linear structures have been prepared under hydro/solvothermal conditions. Of these, I has the chain structure formed by ZnO₄N₂octahedra and SO₄ tetrahedra, while II comprises ladders formed by corner‐sharing four‐membered rings. Amine‐templated thorium sulfates of the formula [HN(CH₂)₆NH]₂[Th₂(SO₄)₆(H₂O)₂]·2H₂O, ( III ) and [H₂N(CH₂)₄NH₂][Th₃(SO₄)₇(H₂O)₄]·5H₂O ( IV ) are also obtained under hydrothermal conditions. III has a sheet structure consisting of cages whereas IV has a two‐dimensional structure derived from the connectivity of ladders.