Angular distributions and excitation functions for elastic and inelastic scattering have been measured with ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, and ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ projectiles on Ca, Ni, Mo, and Sn isotopes. The experimental data show oscillations in the angular distributions which are more pronounced for projectile excitations than for target excitations. These oscillations are discussed within the semiclassical model. The experimental results have been analyzed with the modified distorted-wave Born-approximation (DWBA) code dwuck. The theoretical predictions using conventional (macroscopic form factor) DWBA calculations fail to describe the data accurately; a modification of the form factor is required to achieve a satisfactory description.

NUCLEAR REACTIONS ${}_{}{}^{58,60,62,64}{}_{}{}^{}\mathrm{Ni}$(${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$), (${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$'), (${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$*), $E=63\mathrm{}$ MeV; ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$), (${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$'), $E=61.4\mathrm{}$ MeV; ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$(${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$), (${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$'), (${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$*), $E=72\mathrm{}$ MeV; ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$), (${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$'), $E=70.7\mathrm{}$ MeV; ${}_{}{}^{120}{}_{}{}^{}\mathrm{Sn}$(${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$), (${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$'), (${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$*), $E=72\mathrm{}$ MeV; ${}_{}{}^{122}{}_{}{}^{}\mathrm{Sn}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$), (${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$'), $E=73.95\mathrm{}$ MeV; ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$(${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$), (${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$*), $E=100\mathrm{}$ MeV; $\theta \approx 20-60°$, $\Delta \theta =1\mathrm{}° or 2°$. ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}$(${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$), (${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$'), (${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$*). Measured $\sigma \mathrm{}\left(E\right)\mathrm{}$, $E=30-44\mathrm{}$ MeV, $\Delta E=1-2\mathrm{}$ MeV, $\theta =175\mathrm{}°$; ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$-(${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$), (${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$'), (${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$*). Measured $\sigma \mathrm{}\left(E\right)\mathrm{}$, $E=40-56\mathrm{}$ MeV, $\Delta E=1-2\mathrm{}$ MeV, $\theta =178\mathrm{}°$. (${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$* denotes inelastic excitation of the projectile.) Optical-model, DWBA, and semiclassical analysis.

• Received 19 May 1975

DOI:https://doi.org/10.1103/PhysRevC.12.1945