The ground state properties of the even-even Zn, Ge, Se, Kr, and Sr nuclei are studied in the vicinity of the proton drip line, in a relativistic mean field approach. The knowledge of the properties of these nuclei is crucial in understanding the passage of the r process in astrophysics. The obtained binding energies are shown to be consistent with the measured masses wherever available or otherwise with the mass table of Möller and Nix. The shape coexistence between prolate and oblate structures obtained for ${}_{}{}^{70}{}_{}{}^{}\mathrm{Kr}$ and ${}_{}{}^{72}{}_{}{}^{}\mathrm{Kr}$ isotopes is analyzed in detail.

• Received 22 September 1992

DOI:https://doi.org/10.1103/PhysRevC.48.192