Isospin effect of momentum dependent interaction in heavy ion collisions

We take the isospin degree of freedom in the momentum dependent interaction to obtain an isospin and momentum dependent interaction with a form practically usable in isospin dependent quantum molecular. dynamics model. We investigate the isospin effect of momentum dependent interaction on the observable in the intermediate energy heavy ion collisions. It is found that momentum dependent interaction with and without isospin dependence, lead to significant different predictions on the nuclear stopping (momentum dissipation) and isospin fractionation ratio. In particular the momentum dependent interaction with the isospin degree of freedom induces reductions for the dependence of nuclear stopping on the two-body collisions and the dependence of isospin fractionation ratio on the symmetry potential. However it does not change obviously the features for the nuclear stopping and isospin fractionation ratio as the good probe of in-medium nucleon-nucleon cross section and symmetry potential. The isospin dependence of momentum dependent interaction is thus important for studying accurately the equation of state of isospin asymmetry nuclear matter.