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Heavy-ion collisions often produce fusion barrier distributions with structures displaying a fingerprint of couplings to highly collective excitations. Similar distributions can be obtained from large-angle quasielastic scattering, although in this case, the role of the many weak direct-reaction channels is unclear. For 20Ne+90Zr, we have observed the barrier structures expected for the highly deformed neon projectile; however, for 20Ne+92Zr, we find significant extra absorption into a large number of noncollective inelastic channels. This leads to smearing of the barrier distribution and a consequent reduction in the “resolving power” of the quasielastic method

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We have measured the differential cross-sections for the elastic as well as inelastic scattering populating the 2.43[Formula: see text]MeV [Formula: see text] excited state in [Formula: see text] using [Formula: see text] beams at energies of 30, 40 and 47[Formula: see text]MeV on a [Formula: see text] target. The experimental results for the elastic scattering were analyzed within the framework of the optical model using the Woods–Saxon and double-folding potentials. The theoretical calculations for the concerned excited states were performed using the coupled-channel method. The optimal deformation parameters for the excited states of [Formula: see text] nucleus were extracted.

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This work is a study of the influence of shell effects on the formation of binary fragments in damped collision. We have investigated binary reaction channels of the composite system with Z = 108 produced in the reaction 88 Sr+ 176 Yb at an energy slightly above the Bass barrier (E c.m. /E Bass = 1.03). Reaction products were detected by using the two-arm time-of-flight spectrometer CORSET at the K130 cyclotron of the Department of Physics, University of Jyväskylä. The mass-energy distribution of primary binary fragments has been measured. For targetlike fragments heavier than 190 u, which correspond to a mass transfer as large as twenty nucleons or more, an enhancement of the yields is observed. This striking result can be ascribed to the proton shells at Z = 28 and 82 and implies the persistence of the shell effects in the formation of reaction fragments even for large mass transfers.