Development of an electron-temperature-dependent interatomic potential for molecular dynamics simulation of tungsten under electronic excitation
Development of an electron-temperature-dependent interatomic potential for molecular dynamics simulation of tungsten under electronic excitation
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DOI：
10.1103/physrevb.78.224304
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发表时间：
2008-12-01
影响因子：
3.7
通讯作者：
Duffy, D. M.
中科院分区：
文献类型：
--
作者：
Khakshouri, S.;Alfe, D.;Duffy, D. M.
激光或快速重离子对金属的照射使电子被激发。在激发附近，由于电子-电子碰撞，在10-100 fs的热化时间内建立电子温度。对于短时间，对应于激发后小于1 ps，所产生的电子温度可能比晶格温度高几个数量级。在这短暂的时间内，金属中的原子由于受激发的电子而经历修改的原子间力。这些力可以导致超快的非热现象，如熔化，烧蚀，激光诱导相变和修改振动特性。我们开发了一个电子温度依赖的经验原子间势钨，可以用来模拟这种现象，使用经典的分子动力学模拟。在高电子温度下的温度密度泛函理论计算被用来参数化模型潜力。
Irradiation of a metal by lasers or swift heavy ions causes the electrons to become excited. In the vicinity of the excitation, an electronic temperature is established within a thermalization time of 10-100 fs, as a result of electron-electron collisions. For short times, corresponding to less than 1 ps after excitation, the resulting electronic temperature may be orders of magnitude higher than the lattice temperature. During this short time, atoms in the metal experience modified interatomic forces as a result of the excited electrons. These forces can lead to ultrafast nonthermal phenomena such as melting, ablation, laser-induced phase transitions, and modified vibrational properties. We develop an electron-temperature-dependent empirical interatomic potential for tungsten that can be used to model such phenomena using classical molecular dynamics simulations. Finite-temperature density functional theory calculations at high electronic temperatures are used to parametrize the model potential.