Ab Initio Simulations of Dense Helium Plasmas

学习从头算相场模型

Learning ab initio phase-field models

本文提出一种从分子动力学轨迹学习从头算相场模型的框架，通过神经网络参数化非局域自由能和迁移率，在铁-硼及氢-氦体系中验证了其精度与尺度优势。

Atomistic modeling of the anomalous helium behaviors in vanadium

Ab initio calculations have been performed to clarify the primary behaviors of He atoms in vanadium and to generate the database for the development of the interatomic potential for V-He system within the framework of the"s-band"model.The calculated formation energies of the tetrahedral,octahedral and substitutional He defects,as well as those for He2,He3 and He2V clusters are reasonable when compared with relevant experimental results and ab initio calculations under the same conditions.The applicability of the present V-He potential for atomistic simulations to investigate the moving,cluster…

Statistical Properties of the Dense Hydrogen Plasma: an ab initio Molecular Dynamics Investigation

The metallic regime of the hydrogen plasma is studied by ab initio Molecular Dynamics simulations, for classical protons and fully degenerate electrons, in the strong coupling regime of the protons. The breakdown of linear screening observed for decreasing density gives rise to a surprisingly rich low-temperature phase diagram, showing in particular a dramatic drop of the melting temperature of the proton crystal. Extensive dynamical simulations reveal the remarkable persistence of a weakly damped high-frequency ion acoustic mode (plasmon-like), even under conditions of strong electron screeni…

Properties of Dense Fluid Hydrogen and Helium in Giant Gas Planets

Equilibrium properties of hydrogen-helium mixtures under thermodynamic conditions found in the interior of giant gas planets are studied by means of density functional theory molecular dynamics simulations. Special emphasis is placed on the molecular-to-atomic transition in the fluid phase of hydrogen in the presence of helium. Helium has a substantial influence on the stability of hydrogen molecules. The molecular bond is strengthened and its length is shortened as a result of the increased localization of the electron charge around the helium atoms, which leads to more stable hydrogen molecu…

气态巨行星中氢-氦不混溶边界

Hydrogen-helium immiscibility boundary in gas-giant planetary interiors from machine-learning molecular dynamics

研究通过机器学习势能计算氢-氦不混溶边界，揭示其影响气态巨行星中氦雨形成，为行星模型提供关键数据。

面向太阳能热利用的TiCN基金属陶瓷中碳化钨电子结构与光学性质的第一性原理计算

Ab initio calculation for electronic structure and optical property of tungsten carbide in a TiCN-based cermet for solar thermal applications

本文通过第一性原理计算研究TiCN基金属陶瓷中WC的电子结构与光学性质，发现其约0.6 eV的低能等离子体激发和清晰等离子体边使其具有优异光热转换性能，适合作为太阳能选择性吸收材料。

Hardening and Strain Localisation in Helium-Ion-Implanted Tungsten

Tungsten is the main candidate material for plasma-facing armour components in future fusion reactors. In-service, fusion neutron irradiation creates lattice defects through collision cascades. Helium, injected from plasma, aggravates damage by increasing defect retention. Both can be mimicked using helium-ion-implantation. In a recent study on 3000 appm helium-implanted tungsten (W-3000He), we hypothesized helium-induced irradiation hardening, followed by softening during deformation. The hypothesis was founded on observations of large increase in hardness, substantial pile-up and slip-step f…

掺杂石墨烯中库仑拖曳驱动的电子-空穴双流体性的从头算研究

Ab initio study of Coulomb drag driven electron-hole bifluidity in doped graphene

通过从头算玻尔兹曼输运计算，发现强库仑拖曳效应可在掺杂石墨烯的电子-空穴等离子体中诱导负电导和联合电子-空穴流体动力学（双流体性），并揭示了微观散射机制的作用。

一种模拟高辐照钨中氦和氢的经验势

An empirical potential to simulate helium and hydrogen in highly irradiated tungsten

本研究开发了一种快速EAM势，用于模拟钨中氦和氢的相互作用，并通过热力学模型预测充气空洞能量，经分子动力学验证。

Helium ordered trapping in arsenolite under compression: Synthesis of He2As4O6

The compression of arsenolite (cubic As2O3) has been studied from a joint experimental and theoretical point of view. Experimental X-ray diffraction and Raman scattering measurements of this molecular solid at high pressures with different pressure-transmitting media have been interpreted with the help of ab initio calculations. Our results confirm arsenolite as one of the softest minerals in absence of hydrogen bonding and provide evidence for helium trapping above 3 GPa between adamantane-type As4O6 cages, thus leading to a new compound with stoichiometry He2As4O6. Helium trapping alters all…