Researchers at Institute of Modern Physics, Chinese Academy of Sciences (IMP) have studied the dynamical deformation (DyD) with transport theory in the frame of dinuclear system (DNS) model.
To develop a DNS conception, DyD and nucleon transfer in the heavy ion fusion reaction process were viewed simultaneously as a diffusion process by solving a set of master equations with the variables of the quadrupole deformation of each nucleus and the mass asymmetry variable in the potential energy surface of the system. In addition, a three-step difference scheme was adopted to solve the three-variable partial differential equations numerically.
The DyD evolution with interaction time (fig.1) and the time to reach equilibrium at different mass asymmetry were obtained. Based on the new DNS model, a perfect calculation about the quasifission mass yields in the formation of superheavy nucleus (SHN) was obtained (fig.2), and the experimental data was reproduced very well for the first time. It might conclude that the DyD plays a very important role in the quasifission process. Besides, the effect of DyD on fusion probability was studied. This work is important for the studies of SHN formation and mass transfer mechanism.
The results have been published in Phys.Rev.C 84, 064619 (2012).
The article can be linked as follows: http://prc.aps.org/abstract/PRC/v84/i2/e064619.
Fig.1 Mean values of the deformations of fragments A1 and A2 at different reaction times for the reaction 48Ca + 244Pu with E*= 33 MeV. Groud state (GS), 0.5, 2, 8, and 20 indicate the times t = 0, 0.5, 2, 8, and 20 × 10−22 s, respectively. (Image by IMP)
Fig.2 Quasifission mass yield for the reaction 48Ca + 244Pu with E*= 33 MeV. (Image by IMP)
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