Extension of the Radioactive Series,Z=N±1

The radioactive positron emitters ${\mathrm{Si}}^{27}$, ${\mathrm{S}}^{31}$ and ${\mathrm{A}}^{35}$ were produced by 15-Mev alpha-particles while ${\mathrm{Sc}}^{41}$ was obtained by 8-Mev deutrons. The half-lives of these elements have been determined as 4.92±0.1 seconds, 3.18±0.04 seconds, 1.88±0.04 seconds, and 0.87±0.03 seconds, respectively. The upper limit of the energies of the positrons emitted by ${\mathrm{S}}^{31}$, ${\mathrm{A}}^{35}$, and ${\mathrm{Sc}}^{41}$ were measured and found to be 3.87±0.15 Mev, 4.41±0.09 Mev, and 4.94±0.07 Mev, respectively. The Coulomb energies of the "extra proton" of the nuclei of the $Z-N=1\mathrm{}$ were calculated according to two nuclear models. The variations in the Coulomb energies indicate a nuclear "shell" structure similar to that given by the Hartree model of the nucleus.