ELASTIC AND INELASTIC-SCATTERING OF O-16 AND O-18 IONS FROM ZN-64 AT ENERGIES NEAR THE COULOMB BARRIER

Coulomb-nuclear interference effects were investigated in the inelasti c scattering of O-16 and O-18 by Zn-64. Measurements of elastic and in elastic angular distributions of O-18 were performed at a laboratory e nergy of 49 MeV, over the angular range from theta(lab) approximately 30-degrees to 85-degrees. The excitation functions of O-16 and O-18 io ns were measured at incident energies between 29 and 46 MeV at theta(l ab) = 174-degrees. The experimental angular distributions show structu res which are more pronounced for projectile excitation than for targe t excitation. The interference minimum for the excitation of the O-18 first 2+ state was found to be shifted towards forward angles by appro ximately 5-degrees(c.m.) with respect to the distorted-wave Born appro ximation calculations and by approximately 3.5-degrees(c.m.) with resp ect to the coupled-channels calculations. A pronounced Coulomb-nuclear interference minimum was seen in the excitation of Zn-64(2+) state by inelastic scattering of O-16 projectiles, whereas no pronounced minim um was observed in target excitation by O-18 projectiles. The elastic scattering data were analyzed with the optical model. The inelastic di fferential cross sections for the excitation of the first 2+ states in the target and in the O-18 projectile were analyzed using the distort ed-wave Born approximation and also the coupled-channels approach with collective form factors.