Quantum Monte Carlo Shell Model

我们用蒙特卡罗壳层模型研究了各种原子核的结构。研究了N=20附近原子核的不稳定性。计算范围从偶偶核的yrast态到奇A核和一般核的非yrast态。Yrast态的一些结果已经被实验所验证。能级、电磁跃迁矩阵元素、磁矩有待确认。对于奇A核，对F和Na同位素进行了计算。特别是，我们已经成功地计算了F同位素的滴线。在不稳定核中，N=20时壳层能隙的减小是我们理论研究的重点，也是F同位素滴线延伸很远的原因。提出了一个关于不稳定核中幻数的新理论，并预言了新的幻数。对于PF壳层核，其中间部分的核通过经验调整在G-矩阵的基础上创造了新的有效相互作用而成为可解释的。现在可以描述大约100个原子核，它们在r-过程和RP-过程的研究中很重要。研究了^&lt；56&gt；Ni的球状基态、形变带和超形变带。这项研究正在扩展到A=50-100的原子核。对于重核，首次从微观上描述了形状相变和γ不稳定形变。8台配备Alpha 21164的工作站和4台配备Alpha 21264的工作站已被用作并行处理机。实现了对基法。进行了常规计算，得出了^&lt；16&gt；O闭合壳体断裂的结果。

We have studied the structure of a variety of nuclei by using Monte Carlo Shell Model. Unstable of nuclei around N=20 are studied. The calculations cover from yrast states of even-even nuclei to odd-A nuclei and non-yrast states of general nuclei. Some results for yrast states have been verified already by experiments. Energy levels, elecyromagnetic transition matrix elements, magnetic moments are to be confirmed. As for odd-A nuclei, calculations have been carried out for F and Na isotopes. In particular, we have succeeded in accounting the dripline of F isotopes. The decrease of shell gap at N=20 in unstable nuclei is the major point of our theoretical investigation, and is the cause of the far-extended dripline of F isotopes. A new theory on magic numbers in unstable nuclei has been proposed with predictions of new magic numbers. As for pf-shell nuclei, the nuclei in its middle part have become accountable by creating a new effective interaction based upon G-matrix with empirical adjustments. About 100 nuclei can now be described, which are important in the study of r-process and rp-process. The spherical ground state, deformed band and superdeformed band have been studied for ^<56>Ni. This study is being extended to nuclei with A=50-100. Regarding heavy nuclei, the shape phase transition and γ-unstable deformation have been described microscopically for the first time. Computers such as 8 workstations with Alpha 21164 and 4 workstations with Alpha 21264 have been acquires as parallel processors. The pair-basis method has been implemented. Conventional calculations have been carried out, producing results on the breaking of closed shell in ^<16>O.