Quasiprojectile and intermediate velocity isotopic ratios for light fragments emitted in the 36Ar+58Ni and 58Ni+58Ni reactions between 32 and 84 AMeV

Isotopic ratios for light fragments (Z≤4) emitted by the quasiprojectile (QP) and the mid-rapidity (MR) sources are investigated by the use of a slightly asymmetric system (Ar36+Ni58) and a symmetric one (Ni58+Ni58) for six energies between 32A and 84A MeV and three semiperipheral centrality range selections. Experimental data come from the INDRA 4π multidetector. The results show a clear neutron-rich isotope production from the MR region as compared to the QP source. The beam energy and the centrality also show interesting different trends depending on the charge of the fragments and the emission source. Experimental results are compared to antisymmetrized molecular dynamics simulations.