The ${}_{}{}^{100}{}_{}{}^{}\mathrm{Mo}$($t$,${}_{}{}^3{}_{}{}^{}\mathrm{He}$)${}_{}{}^{100}{}_{}{}^{}\mathrm{Nb}$ reaction has been used to determine the mass and the energy levels of ${}_{}{}^{100}{}_{}{}^{}\mathrm{Nb}$. A mass excess of - 79480±30 keV is obtained for ${}_{}{}^{100}{}_{}{}^{}\mathrm{Nb}$, in substantial disagreement with $\beta$-decay results. Twentytwo excited states of ${}_{}{}^{100}{}_{}{}^{}\mathrm{Nb}$ with $E_x<1.3\mathrm{}$ MeV have been observed.

NUCLEAR REACTION ${}_{}{}^{100}{}_{}{}^{}\mathrm{Mo}$($t$,${}_{}{}^3{}_{}{}^{}\mathrm{He}$), $E=23.0\mathrm{}$ MeV; measured $\sigma (E_{{}_{}{}^3{}_{}{}^{}\mathrm{He}},\theta )$. ${}_{}{}^{100}{}_{}{}^{}\mathrm{Nb}$ deduced levels. New mass of ${}_{}{}^{100}{}_{}{}^{}\mathrm{Nb}$.

• Received 6 February 1979

DOI:https://doi.org/10.1103/PhysRevC.19.2068