Continuum Quasiparticle Random Phase Approximation Research Articles

Distribution of the Gamow-Teller strength in90Nband208Bi

The (He-3,t) charge-exchange reaction has been studied at E(He-3)=450 MeV and angles near 0 degrees on targets of Zr-90 and Pb-208. Fragmentation of the Gamow-Teller (GT) strength into separate components of the particle-hole type has been observed. The distribution of the GT strength in Nb-90 and in Bi-208 has been calculated within the continuum quasiparticle random phase approximation and continuum-random-phase approximation approaches, respectively. These components, especially in Pb-208, could be related with the direct, core polarization, and back-spin-flip Gamow-Teller strength.

Weak interaction rates of neutron-rich nuclei and ther-process nucleosynthesis

Weak interaction rates for very short-lived neutron-rich nuclides involved in the r process are mostly beyond the experimental reach at the present time. Accurate theoretical predictions demand a coherent extrapolation of different nuclear properties away from the experimentally known regions. The b-decay and neutrino-capture rates are estimated within the extended Thomas-Fermi plus Strutinsky integral method and the continuum quasiparticle random phase approximation. This approximation on the self-consistent calculation of the ground-state and b-decay properties is described. The large-scale calculations of the b-strength function for stable and short-lived nuclei are performed to estimate, simultaneously, the b-decay and electron neutrino capture rates for nuclides of relevance to the r-process nucleosynthesis. A comparison of the results with existing experimental data, global calculations, and self-consistent microscopic predictions is presented.

Continuum quasiparticle random-phase approximation description of isovectorE1giant resonances

Isovector $E1$ giant resonances in nonmagic nuclei are calculated by using a method which takes into account the single-particle continuum in the framework of a continuum quasiparticle random-phase approximation. A special procedure is formulated which gives the spurious dipole state at zero energy. The calculations are performed in a stable nonmagic tin isotope as well as unstable magic and nonmagic tin isotopes. The role of the single-particle continuum and the spurious dipole state is discussed. It turned out that the first ingredient has a noticeable influence on the resonance form.