α groups and γ-ray transitions have been observed from nuclides produced in the bombardment of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ with ${}_{}{}^{127}{}_{}{}^{}\mathrm{I}$. Two weak α groups were assigned to ${}_{}{}^{162,163}{}_{}{}^{}\mathrm{Ta}$ based on their measured half-lives and excitation functions. With an unambiguous assignment of these two α groups the absolute masses of nuclides in two long α chains, for which ${}_{}{}^{162,163}{}_{}{}^{}\mathrm{Ta}$ form links, can now be deduced with confidence. Absolute masses are thus obtained for some nuclides very far from stability, including ones that are not bound against ground-state proton emission. The simultaneous observation of α groups and γ rays from other nuclides produced in this bombardment also permitted the determination of the upper limits of six new α branching ratios.

• Received 9 December 1991

DOI:https://doi.org/10.1103/PhysRevC.45.1609