亲和力对熔合反应位垒的影响(英文)

Effect of Proximity Force on Potential Barrier in Fusion Reaction

熔合反应的宏观形变位能由推广的液滴模型来确定 ,它包括体积能、表面能、库容能、亲和力效应、质量的不对称性和精确的核半径 .在过去裂变研究中 ,人们假定表面能和库仑能控制着位垒的高度和宽度 .表面能也只考虑表面张量力效应 ,并不包括颈部或刚形成的碎片的表面之间吸引核力的贡献 .在推广的液滴模型中 ,亲和力考虑了这些附加的表面效应 .在两个核的接触点 ,亲和能达到最大值 ,它的两边逐渐减少直到零 .亲和能减少位垒的高度并移动位垒峰的位置 ,它对应于吸引的亲和力和排斥的库仑力之间平衡的两个分开碎片的位置 .研究表明 :对于超重核熔合过程 ,亲和能使得宏观形变位能有一个宽的坑 (pocket) ,它对应于核的大形变 .对于轻的核 -核系统 ,这种现象不出现 .

The macroscopic deformed potential energies for fusion reactions are determined within a generalized liquid drop model (GLDM) which includes the volume—,surface ,and Coulomb energies,the proximity effects,the mass asymmetry,and an accurate nuclear radius. In ordinary fission studies,it is assumed that the surface and Coulomb energies control the hight and width of the barrier. The surface energy E S takes into account only the effect of the surface tension force and does not include the contribution of the attractive nuclear forces between surfaces in regard to the neck or the gap between the nascent fragments. The nuclear proximity energy is adopted to take into account these additional surface effects in general liquid drop model. At the contact point,the proximity energy reaches maximum while it decreases both sides till to zero. The proximity energy decreases the barrier height by several MeV and moves the position of the barrier top forward,which corresponds to two separated fragments in unstable equilibrium by the balance between the attractive nuclear proximity force and the repulsive Coulomb force in the GDLM. It turns out that a wide macroscopic potential pocket in fusion process is formed due to proximity energy and appears at large deformation. This behavior does not appear at the barrier for the fusion reaction of light nucleus nucleus collision.