Investigation of nuclear structure and β-decay properties of As isotopes

Abstract

The nuclear ground state properties of ${}^{67-80}$As nuclei have been investigated within the framework of relativistic mean field (RMF) approach. The RMF model with density-dependent (DD-ME2) interaction is utilized for the calculation of potential energy curves and the nuclear ground-state deformation parameters (${\beta }_2$) of selected As isotopes. Later, the $\beta$-decay properties of As isotopes were studied using the proton–neutron quasi particle random phase approximation (pn-QRPA) model. These include Gamow Tellar (GT) strength distributions, log $\mathrm{ft}$ values, $\beta$-decay half-lives, stellar ${\beta }^{\pm }$ decays and stellar electron/positron capture rates. The ${\beta }_2$ values computed from RMF model were employed in the pn-QRPA model as an input parameter for the calculations of $\beta$-decay properties for ${}^{67-80}$As. The calculated log $\mathrm{ft}$ values were in decent agreement with the measured data. The predicted $\beta$-decay half-lives matched the experimental values within a factor of 10. The stellar rates were compared with the shell model results. Only at high temperature and density values, the sum of ${\beta }^{+}$ and electron capture rates had a finite contribution. On the other hand, the sum of ${\beta }^{-}$ and positron capture rates were sizeable only at low density and high temperature values. For all such cases, the pn-QRPA rates were found to be bigger than the shell model rates up to a factor of 33 or more. The findings reported in the current investigation could prove valuable for simulating the late-stage stellar evolution of massive stars.