Directional correlation measurements in69Ga

Gamma-gamma directional correlation measurements have been made on the 553.35-318.63, 234.79–871.98 and 1,052.02-871.98 keV cascades in⁶⁹Ga from the decay of⁶⁹Ge using a NaI(Tl)-Ge(Li) coincidence set up. On the basis of these measurements the spin parity of 1/2^?, 3/2^?, 3/2^? and 5/2^? have been assigned respectively to the 318.63, 871.98, 1,106.77 and 1,924.00 keV states in⁶⁹Ga. The results have been discussed and compared with the previous works.     

Erratum to: “Theory of extreme correlations using canonical Fermions and path integrals” [Ann. Phys. 343 (2014) 164–199]

Erratum for paper “Theory of extreme correlations using canonical Fermions and path integrals”, B.S. Shastry, Ann. Phys. 343, 164–199 (2014) http://dx.doi.org/10.1016/j.aop.2014.02.005 AOP69618.     

Sustainable and rapid preparation of nanosized Fe/Ni-pentlandite particles by mechanochemistry

In recent years, metal-rich sulfides of the pentlandite type (M₉S₈) have attracted considerable attention for energy storage applications. However, common synthetic routes towards pentlandites either involve energy intensive high temperature procedures or solvothermal methods with specialized precursors and non-sustainable organic solvents. Herein, we demonstrate that ball milling is a simple and efficient method to synthesize nanosized bimetallic pentlandite particles (Fe_4.5Ni_4.5S₈, Pn) with an average size of ca. 250 nm in a single synthetic step from elemental- or sulfidic mixtures. We herein highlight the effects of the milling ball quantity, precursor types and milling time on the product quality. Along this line, Raman spectroscopy as well as temperature/pressure monitoring during the milling processes provide valuable insights into mechanistic differences between the mechanochemical Pn-formation. By employing the obtained Pn-nanosized particles as cathodic electrocatalysts for water splitting in a zero-gap PEM electrolyzer we provide a comprehensive path for a potential sustainable future process involving non-noble metal catalysts.

A sustainable and rapid mechanochemical method for the preparation of bimetallic nanosized pentlandite particles as cathode material is developed and tested within zero-gap PEM cells.     

Fusion, resonances and scattering in12C+12C reaction

The variation of fusion cross-section (σJ_fus) with energy in the¹²C+¹²C collision is linked to the underlying resonance phenomenon through the behavior of reaction cross-section (σ) of which σ_fus is taken as a part. The calculation of σ_fus is done through an energy-dependent imaginary potential in the optical model potential (OMP). Through dispersion relation, such an imaginary potential gives rise to energy-dependent real potential which is incorporated in the OMP. In our calculation, a form of potential for the nuclear part which has a soft repulsive in-built core is introduced based on similar works done earlier. The calculated results of σ_fus are used to explain the oscillatory structure, astrophysical S-factor and the decreasing trend at higher energies of the experimental σ_fus data in the case of¹²C+¹²C system with remarkable success. The potential used for fusion calculation is tested for fitting elastic scattering data at some energies and is found good in forward angles. Further improvement of the fitting of these data is obtained by incorporating a coupling potential in the surface region. About twenty resonances are observed in our calculation in the specific partial waves and some of them are found close to the experimentally identified resonances in¹²C+¹²C reaction. Thus, we provide an integrated and comprehensive analysis of fusion, resonance and scattering data in the best studied case of¹²C+¹²C reaction within the framework of optical potential model.     

Extremely correlated Fermi liquids

We present the theory of an extremely correlated Fermi liquid with U→∞. This liquid has an underlying auxiliary Fermi liquid Green's function that is further caparisoned by extreme correlations. The theory leads to two parallel hierarchies of equations that permit iterative approximations in a certain parameter. Preliminary results for the spectral functions display a broad background and a distinct T dependent left skew. An important energy scale Δ(k[over →],x) emerges as the average inelasticity of the FL Green's function, and influences the photoemission spectra profoundly. A duality is identified wherein a loss of coherence of the ECFL results from an excessively sharp FL.