F. B. Malik

Microscopic 6Li-28Si potential from the energy-density functional theory

The experimental differential cross-sections for the 6Li elastic scattering by 28Si over the incident energies ELi=7.5–99.0u2009MeV and vector analyzing power data at 22.8u2009MeV have been analyzed in terms of a non-monotonic potential, microscopically derived from the energy-density functional (EDF) theory using a realistic two-nucleon potential that incorporates effects of the Pauli principle. The data are accounted for well without any need for renormalization of the potential or adjustment of its parameters. Inclusion of a static spin-orbit potential with the EDF-generated central real one is found to describe satisfactorily the features of the vector analyzing power data.

Non-monotonic potentials and vector analyzing powers of 6,7Li scattering by 12C, 26Mg, 58Ni, and 120Sn

The data on the elastic scattering cross-section (CS) and vector analyzing power (VAP) of 6,7Li incident on 12C , 26Mg, 58Ni and 120Sn nuclei are analyzed in terms of an optical model (OM) potential, the real part of which is generated from a realistic two-nucleon interaction using the energy-density functional (EDF) formalism. The EDF-generated real part of the potential is non-monotonic (NM) in nature. This NM real potential part, without any renormalization, along with an empirically determined imaginary part and spin-orbit potential, embodying the underlying physics of projectile excitation, can successfully account for both CS and VAP data in all four cases. This investigation, for the first time, using the simple OM analysis accounts well for the opposite signs of the VAP data of elastically scattered 6,7Li by 58Ni at Elab≈20u2009MeV and by 120Sn at Elab=44u2009MeV. The ramification of successfully describing the data by the EDF-generated potential to the equation of state of nuclear matter is discussed.

Non-monotonic potential description of alpha–Zr refractive elastic scattering

Experimental differential cross sections of α elastic scattering by 90Zr in the 15.0–141.7 MeV range of the bombarding energies have been analysed within the framework of an optical model using non-monotonic (NM) potentials. These potentials are generated from the energy-density functional theory using a realistic two-nucleon potential coupled with an appropriate consideration of the Pauli principle. The NM nature of the real part of the potential seems to be gradually diminishing at energies beyond 118.0 MeV. The Airy structure of the nuclear rainbow scattering data in the energy range of 79.5–141.7 MeV is for the first time well accounted for by the shallow NM potential. Two potential families, which are located in the real part, bear a linear variation of a volume integral in the energy range 25.0–141.7 MeV with a threshold anomaly at the lower energies. The potential contains an interior repulsive part that, with energy, shifts towards the surface and gradually weakens until it is almost lost in the nuclear surface. The requirement of a deep attractive real part of the nuclear potential seems to be generally non-stringent for describing the nuclear rainbow oscillations. Some discrete ambiguities in the potentials seem to persist even when the ‘exponential falloff’ in the angular distribution following the ‘rainbow angle’ is well reproduced in this investigation using the NM real part of the optical potentials.

NON-MONOTONIC ALPHA- AND 6Li-POTENTIALS FROM ENERGY DENSITY FUNCTIONAL FORMALISM

The present status of the α-nucleus potential, generated from the energy density functional (EDF) formalism using a realistic two-nucleon potential, which incorporates the Pauli principle, is discussed. The EDF potentials, calculated using a density distribution of α-particle that yields a binding energy of 20 MeV with a reasonable root-mean-squared radius and observed density distributions of 6Li and various target nuclei, are found to be shallow and non-monotonic in character. This non-monotonic EDF potential reproduces satisfactorily the experimental elastic scattering data, particularly at energies above the Coulomb barrier. Since the elastic scattering data and the binding energies of all nuclei considered herein are well reproduced using the mean field generated from a realistic two-nucleon potential for nuclear and nucleonic matter, one may conclude to have reasonable information on the equation of states of nuclear and nucleonic matter from a very low to the saturation density from the present investigation.

ALPHA-ALPHA AND ALPHA-NUCLEUS POTENTIALS: AN ENERGY-DENSITY FUNCTIONAL APPROACH

The real parts of the alpha-alpha and alpha-nucleus potential, particularly for 40,44,48Ca and 58Ni targets are determined from a realistic two-nucleon potential using an energy-density functional approach and are found to be non-monotonic with a short range repulsion in their functional forms that are similar to those needed in accounting for elastic scattering data. The deduced alpha-alpha potential has no bound states and the calculated decay width of 8Be of about 6.4 eV at about 200 keV energy is in agreement with the measurement.