Sesé Luis M
Departamento de Ciencias y Técnicas Fisicoquímicas, Facultad de Ciencias, Universidad Nacional de Educación a Distancia (UNED), Avda. Esparta s/n, 28232 Las Rozas, Madrid, Spain.
Entropy (Basel). 2020 Nov 25;22(12):1338. doi: 10.3390/e22121338.
Path integral Monte Carlo and closure computations are utilized to study real space triplet correlations in the quantum hard-sphere system. The conditions cover from the normal fluid phase to the solid phases face-centered cubic (FCC) and cI16 (de Broglie wavelengths , densities ). The focus is on the equilateral and isosceles features of the path-integral centroid and instantaneous structures. Complementary calculations of the associated pair structures are also carried out to strengthen structural identifications and facilitate closure evaluations. The three closures employed are Kirkwood superposition, Jackson-Feenberg convolution, and their average (AV3). A large quantity of new data are reported, and conclusions are drawn regarding (i) the remarkable performance of AV3 for the centroid and instantaneous correlations, (ii) the correspondences between the fluid and FCC salient features on the coexistence line, and (iii) the most conspicuous differences between FCC and cI16 at the pair and the triplet levels at moderately high densities (. This research is expected to provide low-temperature insights useful for the future related studies of properties of real systems (e.g., helium, alkali metals, and general colloidal systems).
路径积分蒙特卡罗方法和封闭计算被用于研究量子硬球系统中的实空间三重关联。条件涵盖从正常流体相到面心立方（FCC）和cI16（德布罗意波长、密度）的固相。重点在于路径积分质心和瞬时结构的等边和等腰特征。还进行了相关对结构的补充计算，以加强结构识别并促进封闭评估。所采用的三种封闭方法是柯克伍德叠加法、杰克逊 - 芬伯格卷积法及其平均值（AV3）。报告了大量新数据，并得出了关于以下方面的结论：（i）AV3在质心和瞬时关联方面的显著性能；（ii）共存线上流体和FCC显著特征之间的对应关系；（iii）在中等高密度（ ）下，FCC和cI16在对和三重关联水平上最明显的差异。这项研究有望为未来对实际系统（如氦、碱金属和一般胶体系统）性质的相关研究提供有用的低温见解。
