采用同位旋相关的量子分子动力学模型 ,研究了在轰击能量为 40MeV u和 10 0MeV u时 ,1 1 2 Sn +1 1 2 Sn和1 2 4Sn +1 2 4Sn反应产物的同位素分布 .发现在 40MeV u时 ,同位素分布与入射体系的同位旋密切相关 ;而在 10 0MeV u时 ,对这两种不同同位旋体系给出几乎相同的同位素分布 .这种同位素分布的能量依赖性为研究化学不稳定性及其与力学不稳定性的竞争提供了新途径 Isotope-related quantum-molecular dynamics model was used to study the isotopic distribution of the reaction products of 1 1 2 Sn +1 1 2 Sn and 1 2 4Sn + 1 2 4Sn at bombardment energies of 40 MeVu and 10 0MeVu. At 40MeVu, the isotopic distribution is closely related to the isospin of the incident system, whereas at 10MeVu, nearly identical isotopes are given to the two different isospin systems. The energy dependence of this isotope distribution is that the study chemistry Stability and its competition with mechanical instability provide a new way