Uranium oligomerization in chloride-based high temperature melts: in situ XAS studies

In situ EXAFS spectroscopic studies of uranium compounds in high temperature alkali chloride melts indicate the presence of oligomeric species. An investigation into UCl(3) and UCl(4) dissolved in LiCl reveals long range ordering of uranium atoms in the molten state which is not maintained on quenching. Studies of uranium dioxide dissolved in LiCl-KCl eutectic with HCl exhibit long range ordering in both molten and quenched states, and the EXAFS data can be modeled using multiple coordination shells.     

Are there low-lying,intrashell-excited,highly deformed states in the 1f-2p shell nuclei?

It is shown that the improved effective interactions in the fp shell imply the existence of an excited band of states which is much more deformed than the ground state band for some fp shell nuclei. Such states are to a certain extent analogous to the fission isomers occurring in heavy nuclei. Their experimental identification would be interesting and might also help to further improve the effective interaction.     

Energy transfer from Tb3+ to Nd3+ in glycerol:D2O solution and frozen glass

The mechanism of energy transfer from Tb³⁺ to Nd³⁺ in glycerol:D₂O solution at 280 K, 300 K and in its frozen glass at 80 K, 120 K, 190 K and 250 K has been examined. Analysis of the intensity and lifetime measurements of ⁵D₄ level of Tb³⁺ shows that at 280 K and 300 K in solution the transfer rate varies as the square of the Nd³⁺ concentration. This suggests a dipole-dipole transfer in the glycerol:D₂O solution. However, at lower temperatures up to 190 K, where the solution freezes into a glass, the dependence observed is linear at lower Nd³⁺ concentrations and quadratic at higher concentrations. Moreover, the linear concentration dependence becomes more pronounced as the temperature of the glass is increased. This linear concentration dependence of the transfer rate and its temperature dependence have been ascribed to the migrational transfer accompanying the multipolar transfer. The coefficients of both the interactions at the above temperatures have been calculated.     

Minimization of energy variance for a determinantal state as a useful variation on the hartree-fock theme

It is suggested that a single determinantal state in the neighbourhood of the Hartree-Fock state, having the minimum energy variance might be a ‘better’ intrinsic state for describing some of the low energy states of a nucleus. At higher excitation energies the resulting orbitals may provide a suitable single-particle basis for describing the nuclear level density at that energy.     

The energy spectra and electromagnetic transitions of odd-a titanium isotopes

The isotopes ^{55, 47, 49, 51}Ti are studied in the framework of the deformed configuration mixing shell model. The calculated spectra and electromagnetic properties agree well with the observed ones. The calculations suggest the existence of an excited $\text{K =}\text{1}\text{2}$ band of states in ^{45, 47, 49}Ti and a $\text{K =}\text{7}\text{2}$ band in ⁵¹Ti. In ⁴⁹Ti this excited $\text{K =}\text{1}\text{2}$ band is more deformed than the “ground state band”. On the basis of the overall agreement between the calculated and experimental spectra and decay properties we suggest the spin assignments $\text{J =}\text{5}\text{2}$, $\text{7}\text{2}$, $\text{9}\text{2}$, $\text{5}\text{2}$ and $\text{7}\text{2}$ to the states in ⁴⁷Ti observed at 2.168, 2.97, 2.408, 2.835 and 3.223 MeV, respectively.     

Collective Modes and Elastic Constants of Liquid Al83Cu17 Binary Alloy

The collective dynamics （longitudinal and transverse phonon modes） are studied for aluminum-copper （Al-Cu） binary alloy in terms of the eigen-frequencies of the localized collective excitations. The model pseudopotential formalism is employed using a self-consistent phonon scheme by involving multiple scattering and phonon eigen- frequencies. These frequencies are expressed in terms of many-body correlation functions of atoms as well as of interatomic potential. The important ingredients in the present study are the pair-potential and pair-correlation functions. The most recent and sparingly used local field correlation functions are employed to investigate the influence of the screening effects on the vibrational dynamics of non-crystalline Al83Cu17 binary alloy. The results for the elastic constants like bulk modulus BT, rigidity modulus C, Poisson＇s ratio ξ, Young＇s modulus Y, Debye temperature 8D, propagation velocity of elastic waves and dispersion curves are reported based on the collective modes of this binary alloys. The present results are consistent and confirm the applicability of model potential and self-consistent phonon theory for such studies.     

Thermodynamic properties of 3C-SiC

In the present paper, we report on the results of various thermodynamic properties of 3C-SiC at high pressure and temperature using first principles calculations. We use the plane-wave pseudopotential density functional theory as im- plemented in Quantum ESPRESSO code for calculating various cohesive properties in ambient condition. Further, ionic motion at a finite temperature is taken into account using the quasiharmonic Debye model. The calculated thermody- namic properties, phonon dispersion curves, and phonon densities of states at different temperatures and structural phase transitions at high pressures are found to be in good agreement with experimental and other theoretical results.     

A convenient one-pot synthesis of N-fused 1,2,4-triazoles via oxidative cyclization using chromium (VI) oxide

A facile one-pot synthesis of N-fused 1,2,4-triazoles from heterocyclic hydrazines and aldehydes is reported. The reaction is efficiently promoted by chromium (VI) oxide to afford the desired products mostly in high yields and in relatively short time. The high yield of the products and short reaction time are notable advantages of the developed protocol. This protocol is effective toward various substrates having different functionalities.     

A convenient one-pot synthesis of 3,5-diarylisoxazoles via oxidative cyclisation using catalytic CuBr2 and oxone

A facile one-pot synthesis of 3,5-diarylisoxazoles from α,β-unsaturated ketones and hydroxylamine hydrochloride is reported. The reaction is efficiently promoted by catalytic CuBr₂ and Oxone to afford the desired products mostly in high yields and in relatively short time. The mild nature of the synthesis and short reaction time are notable advantages of the developed protocol. This protocol is effective toward various substrates having different functionalities.