Lustig Rolf
Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, Ohio 44115, USA.
J Chem Phys. 2024 Sep 21;161(11). doi: 10.1063/5.0220788.
A novel statistical mechanical methodology is applied to clusters of N ≤ 7 atoms. Exact statistical analogs for any energy derivative of entropy ∂mS/∂Em are used in rigorous microcanonical Monte Carlo simulations to vastly enlarge the pool of measurable thermodynamic properties relative to previous work. All analogs are given for two alternative partition functions of the microcanonical ensemble. Coarse grained energy distributions are used to establish the existence of melting transitions. LJ7, LJ5, and LJ4 are found to exhibit trimodal distributions, a feature not being reported before. Varieties of combinations of entropy derivatives are tested for a direct detection of the melting region. It is shown that for such a purpose, derivatives of at least fourth order are necessary.
一种新颖的统计力学方法被应用于N≤7个原子的团簇。在严格的微正则蒙特卡罗模拟中，使用熵的任何能量导数∂mS/∂Em的精确统计类似物，相对于先前的工作，极大地扩大了可测量热力学性质的范围。所有类似物都是针对微正则系综的两种替代配分函数给出的。粗粒化能量分布用于确定熔化转变的存在。发现LJ7、LJ5和LJ4呈现三峰分布，这是之前未报道过的特征。测试了熵导数的各种组合，以直接检测熔化区域。结果表明，为此目的，至少需要四阶导数。
