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Analyzing powers and cross sections for the elastic scattering of polarized 7 Li by targets of 6 Li, 7 Li and 12 C are shown to depend only on the properties of the projectile for momentum transfers of less than 1.0 fm −1 . The result of a detailed analysis of the experimental data within the framework of the coupled channels model with ground state reorientation and transitions to the excited states of the projectile and targets included in the coupling schemes are presented. This work suggests that nuclear properties of weakly-bound nuclei can be tested by elastic scattering experiments, independent of the target used, if data are acquired for momentum transfers less than ∼ 1.0 fm −1 .

High-spin states in 187Pt have been studied by means of γ-ray spectroscopy techniques. Known bands have been significantly extended and new bands have been found. The band structures are discussed in the framework of the cranking model and negative-parity states are compared with calculations performed with a semi-microscopic axial-rotor plus one-quasiparticle coupling model. Shape coexistence is observed from low excitation energy.

High-spin states in 187Pt have been studied by means of γ-ray spectroscopy techniques. Known bands have been significantly extended and new bands have been found. The band structures are briefly discussed. Fil: Cardona, Maria Angelica. Comisión Nacional de Energía Atómica; Argentina Fil: Hojman, Daniel Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; Argentina Fil: Aguilar, A.. Florida State University; Estados Unidos Fil: Cluff, W.T.. Florida State University; Estados Unidos Fil: Hinners, T.. Florida State University; Estados Unidos Fil: Hoffman, C.R.. Florida State University; Estados Unidos Fil: Lagergren, K.. Florida State University; Estados Unidos Fil: Lee, S.. Florida State University; Estados Unidos Fil: Perry, M.. Florida State University; Estados Unidos Fil: Pipidis, A.. Florida State University; Estados Unidos Fil: Riley, M.A.. Florida State University; Estados Unidos Fil: Tabor, S.L.. Florida State University; Estados Unidos Fil: Tripathi, V.. Florida State University; Estados Unidos

The reaction 13C(alpha,n) is considered to be the main source of neutrons for the s process in asymptotic giant branch stars. At low energies, the cross section is dominated by the 1/2+ 6.356 MeV subthreshold resonance in (17)O whose contribution at stellar temperatures is uncertain by a factor of 10. In this work, we performed the most precise determination of the low-energy astrophysical S factor using the indirect asymptotic normalization (ANC) technique. The alpha-particle ANC for the subthreshold state has been measured using the sub-Coulomb alpha-transfer reaction ((6)Li,d). Using the determined ANC, we calculated S(0), which turns out to be an order of magnitude smaller than in the nuclear astrophysics compilation of reaction rates.

Excited states in $^{20}\mathrm{O}$ were populated in the reaction $^{10}\mathrm{Be}(^{14}\mathrm{C},\ensuremath{\alpha})$ at Florida State University (FSU). Charged particles were detected with a particle telescope consisting of 4 annularly segmented Si surface barrier detectors and $\ensuremath{\gamma}$ radiation was detected with the FSU $\ensuremath{\gamma}$ detector array. Five new states were observed below 6 MeV from the $\ensuremath{\alpha}\mathrm{\text{\ensuremath{-}}}\ensuremath{\gamma}$ and $\ensuremath{\alpha}\mathrm{\text{\ensuremath{-}}}\ensuremath{\gamma}\mathrm{\text{\ensuremath{-}}}\ensuremath{\gamma}$ coincidence data. Shell model calculations suggest that most of the newly observed states are core-excited $1p\mathrm{\text{\ensuremath{-}}}1h$ excitations across the $N=Z=8$ shell gap. Comparisons between experimental data and calculations for the neutron-rich O and F isotopes imply a steady reduction of the $p\mathrm{\text{\ensuremath{-}}}sd$ shell gap as neutrons are added.

Excited states in 20O were populated in the reaction 10Be(14C,alpha) at Florida State University (FSU). Charged particles were detected with a particle telescope consisting of 4 annularly segmented Si surface barrier detectors and gamma radiation was detected with the FSU gamma detector array. Five new states were observed below 6 MeV from the alpha-gamma and alpha-gamma-gamma coincidence data. Shell model calculations suggest that most of the newly observed states are core-excited 1p-1h excitations across the N=Z=8 shell gap. Comparisons between experimental data and calculations for the neutron-rich O and F isotopes imply a steady reduction of the p-sd shell gap as neutrons are added.

We report a measurement of the lifetime of the ${2}_{1}^{+}$ state in $^{18}\mathrm{Ne}$ using the Doppler shift attenuation method, the $^{3}\mathrm{He}(^{16}\mathrm{O},n)$ reaction, and large volume germanium $\ensuremath{\gamma}$-ray detectors of the ``clover'' design. The present measurement gives a $B(E2;{0}_{\mathrm{g}.\mathrm{s}.}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})$ value somewhat lower than that obtained in a previous measurement more than 25 years ago made using the same technique but with a smaller volume germanium detector. In addition, we report a semimicroscopic reanalysis of recent $^{18}\mathrm{Ne}+^{197}\mathrm{Au}$ data on the ${0}_{\text{g.s.}}^{+}\ensuremath{\rightarrow}{2}_{1}^{+}$ transition in $^{18}\mathrm{Ne}$ and compare the $B(E2;{0}_{\text{g.s.}}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})$ results obtained using the two experimental techniques. The comparison between the two methods demonstrates the need for a basis for setting the imaginary part of the optical model potential in the analysis of the scattering experiment before reliable $B(E2;{0}_{\text{g.s.}}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})$ values can be extracted by inelastic scattering when nuclear scattering contributions are significant. The optical model potential could be fixed via a detailed elastic scattering measurement.