基于相对论平均场理论对超重核冷熔合反应截面的研究

在形变约束的相对论平均场理论框架下计算了合成Z=102—118元素的(可能)冷熔合反应中复合核及蒸发一或两个中子剩余核的位能曲面,得到了复合核和剩余核平衡点和鞍点的性质、静态裂变垒高度和冷熔合反应的最佳入射能;利用壳修正和对修正方法计算了平衡点和鞍点的壳修正能、对修正能和微观能.利用由此得到的壳结构信息,用简单的熔合蒸发唯象模型计算了相应反应的冷熔合截面.结果发现,TM1参数提供的结构性质给出了与实验接近的反应截面.

Production Cross Section of Superheavy Nuclei in Cold Fusion Reactions Based on the Relativistic Mean Field Theory

Based on the constrained relativistic mean field (RMF) theory,the potential surfaces of superheavy nuclei from Z=102 to Z=118 are calculated, and the properties of these nuclei are extracted, including binding energy and quadruple deformation of the equilibrium and saddle point, neutron separation energy and the height of the static fission barrier, etc. With the single particle levels obtained from the constrained RMF theory, the shell correction energy, the pairing correction energy and the microscopic energy are obtained by means of Strutinsky shell correction and BCS pairing correction approaches. Production cross sections of superheavy nuclei in cold fusion reactions are estimated by a simple phenomenological model with the above structure information. Using the properties of the compound nucleus and evaporation residue provided by the constrained RMF with TM1 parameters, satisfactory agreement has been obtained with the avaliable experimental production cross sections in cold fusion reactions. The prediction for the production cross section of the nucleus 293118 is two order smaller than the earlier prediction and much more close to the experimental observation. Similar conclusion can also be drawn for 293116.