A molecular dynamics study of laser-excited gold
A molecular dynamics study of laser-excited gold
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DOI：
10.1063/5.0073217
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发表时间：
2022-05-01
影响因子：
5.1
通讯作者：
White, T. G.
中科院分区：
文献类型：
--
作者：
Molina, Jacob M.;White, T. G.
激光激发的金系统的结构演化以前已经通过超快MeV电子衍射测量。然而，原子模拟长期以来一直无法提供熔化过程的一致图像，导致完全熔化的预测阈值能量密度之间存在很大差异，以及异质和均匀熔化之间的过渡。我们利用两个温度经典分子动力学模拟，利用三个非常成功的原子间势，并重现Mo等人提出的电子衍射数据[Science 360，1451-1455（2018）]。我们重新创建的实验电子衍射数据，采用恒定的和温度依赖的电子-离子平衡速率。在所有情况下，我们都能够匹配时间分辨的电子衍射数据，并找到原子模拟和实验之间的一致性，只有通过允许激光能量从相互作用区域传输出去。这种额外的能量损失途径，其规模强烈与激光能量密度，我们归因于热电子离开靶的时间尺度相称的熔化。(c)2022作者。所有文章内容，除非另有说明，均采用知识共享署名（CC BY）许可证（http：//creativecommons.org/licenses/by/4.0/）。
The structural evolution of laser-excited systems of gold has previously been measured through ultrafast MeV electron diffraction. However, there has been a long-standing inability of atomistic simulations to provide a consistent picture of the melting process, leading to large discrepancies between the predicted threshold energy density for complete melting, as well as the transition between heterogeneous and homogeneous melting. We make use of two-temperature classical molecular dynamics simulations utilizing three highly successful interatomic potentials and reproduce electron diffraction data presented by Mo et al. [Science 360, 1451-1455 (2018)]. We recreate the experimental electron diffraction data, employing both a constant and temperature-dependent electron-ion equilibration rate. In all cases, we are able to match time-resolved electron diffraction data, and find consistency between atomistic simulations and experiments, only by allowing laser energy to be transported away from the interaction region. This additional energy-loss pathway, which scales strongly with laser fluence, we attribute to hot electrons leaving the target on a timescale commensurate with melting. (c) 2022 Author(s).All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http:// creativecommons.org/licenses/by/4.0/).