The breakup of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ and ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ into two charged particles following ${\pi }^{-}$ capture is studied. The branching ratios for the reactions ${\pi }^{-}+{}_{}{}^6{}_{}{}^{}\mathrm{Li}\to 2{}_{}{}^3{}_{}{}^{}\mathrm{H} (3.4\mathrm{}\times {10}^{-4\mathrm{}})$, ${\pi }^{-}+{}_{}{}^7{}_{}{}^{}\mathrm{Li}\to {}_{}{}^3{}_{}{}^{}\mathrm{H}+{}_{}{}^4{}_{}{}^{}\mathrm{H} (3.7\mathrm{}\times {10}^{-4\mathrm{}})$, and ${\pi }^{-}+{}_{}{}^7{}_{}{}^{}\mathrm{Li}\to {}_{}{}^3{}_{}{}^{}\mathrm{H}+{}_{}{}^4{}_{}{}^{}\mathrm{H}_{}^{*}{}_{}{}^{} (4\mathrm{}\times {10}^{-4\mathrm{}})$ are measured. The energy of the ground state and first excited state (${}_{}{}^4{}_{}{}^{}\mathrm{H}_{}^{*}{}_{}{}^{}$) of particle-unstable ${}_{}{}^4{}_{}{}^{}\mathrm{H}$ are found to be 2.9 and 6.1 MeV above the energy of the unbound ${}_{}{}^3{}_{}{}^{}\mathrm{H}+n$. An upper limit is set for the branching ratio of the reaction ${\pi }^{-}+{}_{}{}^7{}_{}{}^{}\mathrm{Li}\to {}_{}{}^2{}_{}{}^{}\mathrm{H}+{}_{}{}^5{}_{}{}^{}\mathrm{H} (<\mathrm{}2\mathrm{}\times {10}^{-4\mathrm{}})$.

• Received 9 September 1968

DOI:https://doi.org/10.1103/PhysRev.177.1455