Excitation of nuclear anharmonic vibrations in heavy-ion fusion reactions
نویسندگان
چکیده
We discuss the e ects of multi-phonon excitations on heavy-ion fusion reactions at energies near and below the Coulomb barrier, focusing especially on the role of anharmonicities. We carry out a systematic study of those e ects on the excitation function of the fusion cross section and on the fusion barrier distribution, by using the vibrational limit of the interacting boson model. We also analyze the recently measured high-precision data of the O + Sm fusion reaction with this model and discuss the anharmonic properties of the quadrupole as well as the octupole vibrations in Sm. Negative and positive static quadrupole moments are deduced for the rst 2 and 3 states in Sm, respectively. It is shown that the fusion barrier distribution strongly depends on the sign of the quadrupole moments, suggesting that subbarrier fusion reactions o er an alternative method to extract the static quadrupole moments of phonon states in spherical nuclei. PACS number(s): 25.70.Jj, 21.60.Fw, 21.10.Ky, 27.60.+j
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