论文标题
裂变产量的理论描述:迈向快速有效的全球模型
Theoretical description of fission yields: towards a fast and efficient global model
论文作者
论文摘要
背景:对裂变碎片收益率分布的定量显微镜理解代表了核理论的主要挑战,因为它涉及大振幅核集体运动与单粒子核次运动之间的复杂竞争。 目的:扩展了最近提出的裂变碎片分布的全球建模方法,以说明奇怪的收费产量和中子蒸发的奇异。 方法:裂变轨迹是在密度功能理论框架内获得的,从而可以确定最可能的裂变预盘构型。质量和电荷产率分布是通过统计方法构建的,该统计方法扎根于微型典型集合。 结果:我们表明,提出的杂种模型可以重现实验质量和电荷片段产量,包括奇怪的裂纹核,以用于广泛的裂变核。可以在简单的中子蒸发方案中描述实验同位素产率。我们还探索了异国情调的富含中子和超重系统的裂变片段分布,并将我们的预测与其他最先进的全球计算进行了比较。 结论:我们的研究表明,核子将核子的显微镜重排在裂变片段之前曾经是在分裂之前发生的,并且随后的动力学主要是由核结合的热激发和大量特征驱动的。提出的简单混合方法非常适合涉及数百个裂变核的大规模计算。
Background: A quantitative microscopic understanding of the fission-fragment yield distributions represents a major challenge for nuclear theory as it involves the intricate competition between large-amplitude nuclear collective motion and single-particle nucleonic motion. Purpose: A recently proposed approach to global modeling of fission fragment distributions is extended to account for odd-even staggering in charge yields and for neutron evaporation. Method: Fission trajectories are obtained within the density functional theory framework, allowing for a microscopic determination of the most probable fission prefragment configurations. Mass and charge yields distributions are constructed by means of a statistical approach rooted in a microcanonical ensemble. Result: We show that the proposed hybrid model can reproduce experimental mass and charge fragment yields, including the odd-even staggering, for a wide range of fissioning nuclei. Experimental isotopic yields can be described within a simple neutron evaporation scheme. We also explore fission fragment distributions of exotic neutron-rich and superheavy systems, and compare our predictions with other state-of-the art global calculations. Conclusion: Our study suggests that the microscopic rearrangement of nucleons into fission fragments occurs well before the scission, and that the subsequent dynamics is mainly driven by the thermal excitations and bulk features of the nuclear binding. The proposed simple hybrid approach is well suited for large-scale calculations involving hundreds of fissioning nuclei.