The discovery of the new proton emitter ${}_{}{}^{112}{}_{}{}^{}\mathrm{Cs}$ with an energy of 807±7 keV and a half-life of 500±100 μs is reported. WKB half-life calculations indicate ${\mathit{d}}_{5/2}$ proton emission with a low spectroscopic factor comparable to values for ${}_{}{}^{109}{}_{}{}^{}\mathrm{I}$ and ${}_{}{}^{113}{}_{}{}^{}\mathrm{Cs}$. This behavior is consistent with the onset of deformation in this region. The odd-odd nuclides ${}_{}{}^{112}{}_{}{}^{}\mathrm{Cs}$ and ${}_{}{}^{108}{}_{}{}^{}\mathrm{I}$ have significantly lower ${\mathit{Q}}_{\mathit{p}}$ values than the corresponding isotopes lying closer to stability, which is attributed to strong pairing forces between the odd nucleons. The half-life of ${}_{}{}^{113}{}_{}{}^{}\mathrm{Cs}$ has been measured with improved precision as 17±2 μs.

• Received 8 November 1993

DOI:https://doi.org/10.1103/PhysRevLett.72.1798