The numerical computation of chemical potential in dense, non-homogeneous fluids is a key problem in the study of confined fluids thermodynamics. To this day several methods have been proposed, however there is still need for a robust technique, capable of obtaining accurate estimates at large average densities. A widely established technique is the Widom insertion method, that computes the chemical potential by sampling the energy of insertion of a test particle. Non-homogeneity is accounted for by assigning a density dependent weight to the insertion points. However, in dense systems, the poor sampling of the insertion energy is a source of inefficiency, hampering a reliable convergence.
We have recently presented a new technique for the chemical potential calculation in homogeneous fluids. This novel method enhances the sampling of the insertion energy via Well-Tempered Metadynamics, reaching accurate estimates at very large densities. In this paper we extend the technique to the case of non-homogeneous fluids. The method is successfully tested on a confined Lennard-Jones fluid. In particular we show that, thanks to the improved sampling, our technique does not suffer from a systematic error that affects the classic Widom method for non-homogeneous fluids, providing a precise and accurate result.
Chemical potential of liquids and mixtures via Adaptive Resolution Simulation
我们采用自适应分辨方法AdResS，在其最近开发的类大正则版本（GC-AdResS）[Wang et al. Phys.Rev.X 3，011018（2013）]中，计算各种液体和混合物的过量化学势$μ^{ex}$。我们比较我们的结果与那些从全原子模拟使用热力学积分技术，并显示出令人满意的协议。在GC-AdResS中，计算$μ^{ex}$的程序对应于系统的标准初始平衡过程;这意味着，独立于研究的特定目的，每次进行GC-AdResS模拟时，都会自动计算每种分子种类的$μ^{ex}$。
Fingerprints of antiaromaticity in the negative ion (Li$_3$Al$_4$)$^-$ via an ab initio quantum-chemical study of the equilibrium structure of the inhomogeneous electron liquid
负离子（Li $_3$ Al $_4$）$^-$中的反芳香性指纹，该物种可通过激光汽化技术实现，通过\emph{ab initio}量子化学研究揭示。首先，该离子的基态平衡几何进行了预测。此外，对于相应的非均匀电子液体，HOMO的特性进行了研究，无论是方形和矩形Al $_4$几何形状的两个低洼异构体的负离子。对Al $_4$构型的几何形状变化没有特别的敏感性。因此，我们计算了理论化学位移（NICS），其中包含显着的反芳香性指纹。至于未来的方向，添加了一些与香农熵相关的评论。
Transferability of the chemical bond-based machine learning model for dipole moment: the GHz to THz dielectric properties of liquid propylene glycol and polypropylene glycol
Observation of Iron Oxide to Nitride Conversion via Liquid Liquid Phase Separation in High pressure Borate Melt
Institute of Atomic and Molecular Physics, Sichuan University（四川大学原子与分子物理研究所）；Shanghai Advanced Research Institute, Chinese Academy of Sciences（中国科学院上海高等研究院）
Quantum field theory approach for multistage chemical kinetics in liquids
Voevodsky Institute of Chemical Kinetics and Combustion（Voevodsky化学动力学与燃烧研究所）；Rice University（莱斯大学）；Research Complex at Harwell, Scientific Computing, Science and Technology Facilities Council（哈韦尔研究中心，科学计算，科学与技术设施委员会）
