Observation Of The Z=N+1 Nuclei Y-77(39), Zr-79(40), And Mo-83(42)

The very neutron deficient Z = N + 1 nuclei Y-77(39), Zr-79(40), and Mo-83(42) have been observed for the first time following the fragmentation of a Mo-92 beam. In contrast, no evidence was found for the existence of Nb-81(41) and Tc-85(43). The observation of Y-77(39) is of particular interest in light of the instability of the odd-proton, Z = N + 1 systems, Br-69(35), Rb-73(37), Nb-81(41), and Tc-85(43), and may be explained as a consequence of the shape polarizing effect of the highly deformed, prolate Z = N = 38 core. The experimental results are discussed within the framework of the shell-correction model, which together with proton-decay calculations allow an estimate of the proton separation energies of these highly exotic systems to be calculated.