Molecular resonances in ²⁸Si + ²⁸Si

Wobbling motions observed by angular correlation measurements

¹ Graduate School of Engineering and Resource Science, Akita University, Akita 010-8502, Japan
² Research Center for Nuclear Physics, Osaka University, Ibaraki 567-0047, Japan

^a e-mail: uegaki@phys.akita-u.ac.jp

Published online: 20 March 2014

Abstract

High-spin resonances observed in ²⁸Si+ ²⁸Si collisions are studied with a dinuclear molecular model. At high spins, a stable dinuclear configuration of the oblate-oblate system (²⁸Si + ²⁸Si) is found to be an equator-equator (E-E) touching one. Normal modes have been investigated around the equilibrium, which are expected to be an origin of a large number of the resonances observed. Analyses of physical quantities are made and compared with the recent experimental data measured at Strasbourg. Since the E-E configuration is slightly triaxial, rotations of the total system induce mixing of K quantum numbers, called wobbling motion, which clearly explains the particle-γ angular correlations observed as well as the disalignments observed in the angular distributions, in a simple and natural way. Furthermore, predictions are given for the angular correlations of the wobbling excited states. The importance of the angular correlation measurements is stressed, which provide identification of the dinuclear configurations by spin orientations of the constituent nuclei ²⁸Si.