物理化学学报 >> 2010, Vol. 26 >> Issue (12): 3143-3149.doi: 10.3866/PKU.WHXB20101224

热力学、热化学和溶液化学 上一篇    下一篇

激光诱导铝纳米膜熔化机理的分子动力学模拟

白明泽1, 程丽1, 唐红1, 豆育升1,2   

  1. 1. 重庆邮电大学计算化学研究所, 重庆400065;
    2. Department of Physical Sciences, Nicholls State University, LA 70310, USA
  • 收稿日期:2010-07-22 修回日期:2010-10-12 发布日期:2010-12-01
  • 通讯作者: 豆育升 E-mail:Yusheng.Dou@nicholls.edu
  • 基金资助:

    国家自然科学基金(20773618, 21073242)和重庆邮电大学自然科学基金(A2008-39)资助项目

Molecular Dynamics Simulation of the Laser-Induced Melting of an Al Nanofilm

BAI Ming-Ze1, CHENG Li1, TANG Hong1, DOU Yu-Sheng1,2   

  1. 1. Institue of Computational Chemistry, Chongqing University of Posts and Telecommunications, Chongqing 400065, P. R. China;
    2. Department of Physical Sciences, Nicholls State University, LA 70310, USA
  • Received:2010-07-22 Revised:2010-10-12 Published:2010-12-01
  • Contact: DOU Yu-Sheng E-mail:Yusheng.Dou@nicholls.edu
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20773618, 21073242) and Natural Science Foundation of Chongqing University of Posts and Telecommunications, China (A2008-39).

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摘要：

采用耦合一维双温模型的分子动力学方法研究了纳米级的铝膜在飞秒激光辐照下的熔化机制. 这种方法不仅能够在原子水平上展现金属膜的各种微观行为, 还能有效地描述金属膜的激光能量吸收、传递和金属电子热传导等过程. 模拟结果表明, 与其它金属相比, 铝膜在飞秒激光辐照下的电子温度、晶格温度以及内部压力等呈现出不同的变化. 铝膜在较高强度激光辐照下会很快发生全局一致的熔化, 这与镍膜上下非均匀的熔化不同. 并且由于铝的电子-声子耦合强度较高导致铝膜较镍膜和金膜熔化得更快. 模拟结果显示, 铝膜的熔化时间与实验测量的超快激光诱导的铝膜熔化时间一致. 进而从理论上支持激光诱导的铝膜熔化是一个热力学熔化过程.

关键词: 金属铝, 激光熔化, 双温模型, 超快动力学, 热力学熔化

Abstract:

A coupled computational technique, which combines the one dimensional two-temperature model and molecular dynamics, was used to study the melting dynamics of a nanoscale aluminum film irradiated by a femtosecond laser pulse. The model is capable of providing an atomic-level depiction of fast microscale processes in metals and gives an adequate description of laser light absorption, energy transfer, and fast electron heat conduction in metals. The simulation revealed that the electron temperature, lattice temperature, and laser induced pressure of the Al film were significantly different from those of Ni and Au films. The Al film melts globally soon after laser radiation and this is different from the Ni film, which goes through a step melting process. In addition, the Al film shows a much faster melting process than the Ni and Au films because of strong electron-phonon coupling. The melting time of the Al film by an ultrafast laser pulse is consistent with recent experimental observations, which supports the assertion that the laser induced melting of an Al film is a thermal process.

Key words: Metal Al, Laser melting, Two-temperature model, Ultrafast dynamics, Thermal melting