Alpha-Particle Scattering byNe20at 16.8 MeV

Energy-averaged angular distributions have been measured at 16.8 MeV for scattering to the ground state and first two excited states at ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$. Direct and compound-nuclear contributions have been estimated. Optical-model fits to the elastic scattering data with three discrete real potentials ($V=34, 57, \mathrm{and} 83$ MeV) were greatly improved by an $l$-dependent absorption. Only two well depths (50 and 80 MeV) gave reasonable $0^{+}$-$2^{+}$ coupled-equation fits. Slightly better results for $0^{+}$-$2^{+}$-$4^{+}$ coupling were obtained by including a $j$-dependent absorption with $V=50\mathrm{}$ MeV, $W=4.0\mathrm{}$ MeV, $R=4.94\mathrm{}$ F, ${\beta }_2=0.40\mathrm{}$, and ${\beta }_4=0.0\mathrm{}$.