Fission Fragment Spectroscopy on a $^{28}$Si+$^{28}$Si Quasimolecular Resonance

R. Nouicer, C. Beck, S. J. Sanders, A. Szanto De Toledo, Sl. Cavallaro
Fragment-fragment-$\gamma$ triple coincident measurements of the $^{28}$Si + $^{28}$Si reaction at E$_{lab.}$ = 111.6 MeV carefully chosen to populate J = 38$^{+}$ resonance have been performed at the VIVITRON tandem facility by using Eurogam Phase II $\gamma$-ray spectrometer. In the $^{28}$Si + $^{28}$Si exit-channel, the resonance behavior of the $^{28}$Si + $^{28}$Si reaction at the beam energy is clearly confirmed. An unexpected spin disalignment has been observed in the measured angular
more » ... stributions in the elastic, inelastic, and mutual excitation channels. This disalignment is found to be consistent with particle-$\gamma$ angular correlations and supported by the molecular model prediction of a "butterfly motion". The K$^{\pi}$ = 0$^{+}_{3}$ band corresponding to the large prolate deformation of the $^{28}$Si is more intensely fed in the resonance region. The selective population of high-excited states are discussed within a statistical fusion-fission model. In the $^{32}$S + $^{24}$Mg exit-channel, the spectroscopic study of the $^{32}$S, has revealed the contribution of a new $\gamma$-ray transition $0^{+} (8507.8 keV) \to 2^{+}_{1} (2230.2 keV) $.
doi:10.15161/ fatcat:yixktof5wjbztapkujd25diiqi