We have observed the excitation of the first excited state (${\mathit{E}}_{\mathit{x}}$=0.98 MeV, ${\mathit{J}}^{\mathrm{\pi }}$=$1^{+}$) of the radioactive, neutron-rich nucleus ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$ (${\mathit{J}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{\mathrm{\pi }}$=$2^{+}$) from its inelastic scattering on ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{Ni}$ at E${(}^8$Li)≃14.6 MeV. Cross sections measured out to large ${\mathrm{\theta }}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$ agree well with Coulomb-excitation probabilities and have been used to deduce an E2↑ transition rate for the $2_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{+}$→$1^{+}$ excitation in ${}_{}{}^8{}_{}{}^{}\mathrm{Li}_{}^{\mathrm{*}}{}_{}{}^{}$. The latter [B(E2↑)=55±15 ${\mathit{e}}^2$ ${\mathrm{fm}}^4$] is large relative to nearby stable nuclei, but comparable to the neighboring neutron-rich nucleus ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$. The relevance of the data to predicted ‘‘neutron-halo’’ giant dipole resonances in unstable nuclear projectiles is considered.

• Received 22 March 1991

DOI:https://doi.org/10.1103/PhysRevLett.66.2452