(p,d) Reactions withLi6,Li7, andBe9

Abstract

Excited states of ${}_{}{}^5{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, and ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$ were studied by means of the ($p,d$) reaction, using 33.6-MeV incident protons. Deuteron groups were observed corresponding to strongly excited levels in ${}_{}{}^5{}_{}{}^{}\mathrm{Li}$ at 0.0 and 16.6 MeV; in ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ at 0.0, 2.15, 3.57, and 5.38 MeV; and in ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$ at 0.0, 3.1, 11.4, 16.95, 17.62, 18.18, and 19.21 MeV. Small deuteron yields were observed for excited levels of ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$ at 16.6 and 19.15 MeV. Angular distributions were taken for the strongly excited states, and the results were compared with a distorted-wave Born-approximation (DWBA) calculation. Angular distributions for the elastic scattering of 33.6-MeV protons from targets of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, and ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$ were measured and fitted with an optical-model calculation to obtain the proton optical parameters used in the DWBA analysis. With a few exceptions, which are discussed, the ($p,d$) angular distributions are characteristic of a direct pickup of a $1p$-shell neutron. Spectroscopic factors were extracted from the experimental data and were compared with those obtained from theoretical intermediate-coupling calculations in the $1p$ shell. The results are discussed for the high excited states of ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$, where isotopic-spin mixing is indicated.