论文标题
量子Lennard-Jones固体的相位行为
Phase behaviour of the quantum Lennard-Jones solid
论文作者
论文摘要
Lennard-Jones的电位可能是用于相互作用的最广泛使用颗粒（例如贵重气体固体）的模型之一。已知经典LJ固体的相图在HCP和FCC相之间表现出过渡。但是，量子Lennard-Jones固体的相位行为仍然未知。基于路径积分分子动力学和晶格动力学计算的热力学整合用于研究HCP和FCC Lennard-Jones固体的相位稳定性。 HCP相被证明是通过PIMD中的量子效应稳定的，而FCC被Lattice Dynamics显示出偏爱，这表明可能是高量子系统的重入性低压HCP相。讨论了对贵重气体固体的相位稳定性的影响。对于等于氦气的参数，零点振动引起的膨胀与量子熔化有关：晶体结构在零压力下均不稳定。
The Lennard-Jones potential is perhaps one of the most widely-used models for the interaction of uncharged particles, such as noble gas solids. The phase diagram of the classical LJ solid is known to exhibit transitions between hcp and fcc phases. However, the phase behaviour of the quantum Lennard-Jones solid remains unknown. Thermodynamic integration based on path integral molecular dynamics and lattice dynamics calculations are used to study the phase stability of the hcp and fcc Lennard-Jones solids. The hcp phase is shown to be stabilized by quantum effects in PIMD while fcc is shown to be favoured by lattice dynamics, which suggests a possible re-entrant low pressure hcp phase for highly quantum systems. Implications for the phase stability of noble gas solids are discussed. For parameters equating to Helium, the expansion due to zero-point vibrations is associated with quantum melting: neither crystal structure is stable at zero pressure.
