A 740-keV-wide peak in the ${}_{}{}^6{}_{}{}^{}\mathrm{He}$ spectrum from the bombardment of ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ by 70-MeV ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ particles is identified as the mirror of the ${\mathrm{½}}^{-}$ first excited state of ${}_{}{}^{11}{}_{}{}^{}\mathrm{Be}$. The $Q$ value for the ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$(${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^6{}_{}{}^{}\mathrm{He}$)${}_{}{}^{11}{}_{}{}^{}\mathrm{N}$ reaction to this state is -25.03±0.10 MeV, which corresponds to a mass excess of 25.23±0.10 MeV. The analogs of this state in ${}_{}{}^{11}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ were observed with the ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}\mathrm{}(p,t)\mathrm{}$ and ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}(p,{}_{}{}^3{}_{}{}^{}\mathrm{He})$ reactions, and the excitation energies and widths found to agree well with the previous measurements.

[NUCLEAR REACTION ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}({}_{}{}^3{}_{}{}^{}\mathrm{He},{}_{}{}^6{}_{}{}^{}\mathrm{He})$, $E=70\mathrm{}$ MeV measured $Q$, deduced mass excess of ${}_{}{}^{11}{}_{}{}^{}\mathrm{N}$.]

• Received 11 March 1974

DOI:https://doi.org/10.1103/PhysRevC.9.2130