Systematic study of dynamical dipole mode via the isospin-dependent Boltzmann-Uehling-Uhlenbeck model

Dynamical dipole mode in heavy-ion collisions has been studied by using an isospin-dependent Boltzmann- Uehling-Uhlenbeck （IBUU） model. We investigate the dependence of centroid energy and strength of the γ spectrum on beam energy, N/Z ratio and mass asymmetry. The calculated yield and angular distribution of the γ-ray produced by dynamical dipole emission are consistent with the experimental data. The results show that the detailed study of dynamical dipole radiation can provide information on the isospin evolution of charge- asymmetric heavy-ion collisions around the normal nuclear density.