Isospin momentum-dependent interaction and its role on the isospin fractionation ratio in intermediate energy heavy ion collisions

We investigate the role of isospin momentum-dependent interaction on the isospin fractionation ratio and its dynamical mechanism in the intermediate energy heavy ion collisions, by inserting an isospin de degree of freedom into the momentum-dependent interaction to obtain all isospin momentum-dependent interaction given in a form practically usable in the isospin-dependent quantum molecular dynamics model. It is found that the isospin momentum-dependent interaction brings an important isospin effect, into the isospin fractionation ratio. In particular, the isospin momentum-dependent interaction reduces obviously the reduction of isospin fractionation ratio. Thus the isospin dependence of momentum-dependent, interaction is thus important for studying accurately the equation of state of isospin asymmetry nuclear matter.