非对称核物质的化学不稳定性与力学不稳定性

基于扩展的Skyrme有效相互作用,在Hartree-Fock近似下对非对称核物质的化学不稳定性与力学不稳定性进行了研究,并与简单的三参数势,即所谓的软势与硬势的计算结果进行了比较.结果发现两种模型给出的非对称核物质化学不稳定性与力学不稳定性之间的关系是完全不同的.通过研究化学不稳定性在临界温度附近的行为发现,对软势与硬势,化学不稳定性可能出现在温度高于临界温度的气化(全爆炸)机制中.而对于SKM势参数,化学不稳定性不会出现在温度高于临界温度的气化(全爆炸)机制中.这种差别也反映在压强密度平面上力学不稳定关键词：非对称核物质状态方程化学不稳定性力学不稳定性

CHEMICAL INSTABILITY AND MECHANICAL INSTABILITY IN ASYMMETRIC NUCLEAR MATTER

Using a temperature, density, isospin and momentum dependent equation of state of nuclear matter obtained within the framework of Extended Skryme Hartree Fock theory, we study the chemical and mechanical instabilities of nuclear matter at different temperatures, density and relative neutron excess,and compare them with the results of the simplified three-parameter potentials, namely soft and hard potentials in which the symmetry energy part is added by hand. It is found that the asymmetric nuclear matter has remarkable chemical instability in the mechanically stable region. The relationship between the mechanical and chemical instabilities is different from the result of soft and hard potentials, which is shown to result from the difference of the density dependence form of single particle potentials. We also provide the chemical and mechanical spinodal regions in pressure density plane, and their isospin dependence is discussed. In particular, the behaviours of chemical instability around the critical temperature and the possible consequences in heavy ion collisions at intermediate energy are investigated.