On the peak mass production of different fragments in intermediate-energy heavy-ion collisions

Using the isospin-dependent quantum molecular dynamics (IQMD) model, we study the system mass dependence of the peak center-of-mass energy (E_c.m. ^max) and maximal production (left angle N right angle ^max) of various mass fragments at their corresponding E_c.m. ^max. We studied, in particular, light clusters (LCs), medium-mass fragments (MMFs) and heavy-mass fragments (HMFs) produced in various reactions ranging from ⁴⁰Ca + ⁴⁰Ca to ¹⁹⁷Au + ¹⁹⁷Au. Our findings show that the E_c.m. ^max and left angle N right angle ^max increase with the system mass for all mass fragments except for HMFs where the peak center-of-mass energy decreases and corresponding multiplicity remains constant with the system mass. This happens due to the dominant role of Coulomb interactions in heavier colliding nuclei. Experiments are called for to verify this prediction. (orig.)