Nuclear quantum effects on the high pressure melting of dense lithium
Nuclear quantum effects on the high pressure melting of dense lithium
复制标题
核量子效应对致密锂高压熔化的影响
DOI：
10.1063/1.4907752
复制
发表时间：
2015-02-14
影响因子：
4.4
通讯作者：
Wang, Enge
中科院分区：
文献类型：
--
作者：
Feng, Yexin;Chen, Ji;Wang, Enge
采用自行开发的热力学积分和从头算路径积分分子动力学方法相结合的方法，定量研究了45 GPa下核量子效应（NQE）对致密锂熔化的影响.我们发现，虽然NQE显着改变竞争的固相和液相的自由能，熔化温度（Tm）降低仅类似于15 K，与使用经典和量子核在接近一个新的实验获得的值。除此之外，观察到接近T-m的固/液自由能差的大幅缩小，与玻璃态在快速冷却时可能形成的趋势一致。这一趋势被证明在两相模拟，这有助于调和最近的两个实验之间的一个重要冲突的结晶动力学。这项研究提供了一个简单的图片，在压力下的相图锂。这也表明，索赔的影响，NQE的相图，应仔细作出和所采用的方法提供了一个强大的解决方案，这样的定量分析。(C)2015 AIP Publishing LLC.
Using a self-developed combination of the thermodynamic integration and the ab initio path-integral molecular dynamics methods, we quantitatively studied the influence of nuclear quantum effects (NQEs) on the melting of dense lithium at 45 GPa. We find that although the NQEs significantly change the free-energies of the competing solid and liquid phases, the melting temperature (T-m) is lowered by only similar to 15 K, with values obtained using both classical and quantum nuclei in close proximity to a new experiment. Besides this, a substantial narrowing of the solid/liquid free-energy differences close to T-m was observed, in alignment with a tendency that glassy states might form upon rapid cooling. This tendency was demonstrated by the dynamics of crystallization in the two-phase simulations, which helps to reconcile an important conflict between two recent experiments. This study presents a simple picture for the phase diagram of lithium under pressure. It also indicates that claims on the influence of NQEs on phase diagrams should be carefully made and the method adopted offers a robust solution for such quantitative analyses. (C) 2015 AIP Publishing LLC.