We have measured differential cross sections for elastic and inelastic scattering of ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ + ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ at a lab energy of 131 MeV. Inelastic data for exciting the ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ $2^{+}$ (1.63 MeV) state and a group of states near 4.2 MeV are presented. The data are analyzed by a rotational-model coupled-channels calculation including the ground state, $2^{+}$,and $4^{+}$ states of ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$. We obtain the values: transition moment $B\left(E2\mathrm{}\uparrow \right)=(0.0330\mathrm{}\pm 0.0015)$ ${\mathit{e}}^2$ ${\mathrm{b}}^2$, intrinsic hexadecapole moment $Q_{40}=(0.022\mathrm{}\pm 0.003)$ ${\mathit{e}}^2$ ${\mathrm{b}}^2$, and static quadrupole moment for the ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ $2^{+}$ state $Q_2=(-0.27\mathrm{}\pm 0.03)$ e b. The result for $Q_2$ emphasizes a discrepancy with the rotational model and with various shell model calculations.

NUCLEAR REACTIONS ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ (${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$, ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$), ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ (${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$, ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}\prime$), $E=131\mathrm{}$ MeV, measured $\sigma \left(\theta \right)$; deduced optical potential, quadrupole deformation parameter, hexadecapole deformation parameter, and static quadrupole moment of ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ by a coupled-channels analysis. Enriched target.

• Received 12 December 1977

DOI:https://doi.org/10.1103/PhysRevC.17.1665