Using the nuclear symmetry energy that has been recently constrained by the isospin diffusion data in intermediate-energy heavy ion collisions , we have studied the transition density and pressure at the inner edge of neutron star crusts , and they are found to be 0.040 fm ^ { -3 } \leq \rho _ { t } \leq 0.065 fm ^ { -3 } and 0.01 MeV/fm ^ { 3 } \leq P _ { t } \leq 0.26 MeV/fm ^ { 3 } , respectively , in both the dynamical and thermodynamical approaches .
We have also found that the widely used parabolic approximation to the equation of state of asymmetric nuclear matter gives significantly higher values of core-crust transition density and pressure , especially for stiff symmetry energies .
With these newly determined transition density and pressure , we have obtained an improved relation between the mass and radius of neutron stars .