Gamow-Teller response in deformed even and odd neutron-rich Zr and Mo isotopes

Abstract

β-decay properties of neutron-rich Zr and Mo isotopes are investigated within a microscopic theoretical approach based on the proton-neutron quasiparticle random-phase approximation. The underlying mean field is described self-consistently from deformed Skyrme Hartree-Fock calculations with pairing correlations. Residual separable particle-hole and particle-particle forces are also included in the formalism. The structural evolution in these isotopic chains including both even and odd isotopes is analyzed in terms of the equilibrium deformed shapes. Gamow-Teller strength distributions, β-decay half-lives, and β-delayed neutron-emission probabilities are studied, stressing their relevance to describe the path of the nucleosynthesis rapid neutron capture process.

β-decay properties of neutron-rich Ge, Se, Kr, Sr, Ru, and Pd isotopes from deformed quasiparticle random-phase approximation

“…The cases of Zr and Mo isotopes were discussed in Refs. [37,38]. Both oblate and prolate minima are observed in the lighter isotopes of Zr and Mo with prolate ground states.…”

“…Zr and Mo isotopes were already studied in Refs. [37,38] and are not repeated here. excitation energy as the number of neutrons N increases in a given isotopic chain.…”

“…An optimum set of coupling strengths could be chosen following a case-by-case fitting procedure and one will finally get different answers depending on the nucleus, shape, and Skyrme force. However, because the purpose here is to test the ability of QRPA to account for the GT strength distributions in this mass region with as few free parameters as possible, the same coupling strengths are used for all the nuclei considered in this paper, which are taken from previous works [37,38]. We use χ ph GT = 0.15 MeV and κ pp GT = 0.03 MeV for the residual interaction in the ph and pp channels, respectively.…”

“…One can understand from simple qualitative arguments that the role of FF transitions is expected to be more important in lighter Ge and in Pd isotopes. Thus, for 32 Ge, 34 Se, 36 Kr, and 38 Sr isotopes, the last occupied proton orbitals come basically from the 2p 3/2 ,1f 5/2 , and 2p 1/2 negative-parity spherical shells. On the other hand the neutrons in 80−94 Ge isotopes occupy orbitals belonging to the 1g 9/2 ,2d 5/2 , and 1g 7/2 positive-parity spherical shells.…”

“…[37,38] the decay properties of neutron-rich Zr and Mo isotopes were studied within a deformed proton-neutron QRPA based on a self-consistent Hartree-Fock (HF) mean field formalism with Skyrme interactions and pairing correlations in BCS approximation. Residual spin-isospin interactions were also included in the particle-hole and particle-particle channels [39,40].…”