飛秒雷射加工材料時，將會攜帶相當大的能量，此強大的能量將導致雷射與材料間發生庫倫爆炸等粒子高速運動的現象，此種高速粒子運動的現象無法使用傳統分子動力學來有效模擬，故本論文發展相對論分子動力學來模擬高速粒子之運動，並將庫倫力導入Lennard-Jones 勢能當中，來有效模擬經由庫倫爆炸後之帶電粒子高速運動。此相對論分子動力學中除了利用一些分子動力學加速運算技巧，例如：Verlet list、r-cut、Cell list等，並將程式平行化來計算大尺度之飛秒雷射加工現象，系統模擬粒子數達到百萬顆，可以清楚的看到材料經飛秒雷射加工後之孔洞，並分析經飛秒雷射加工後材料之應力分佈與溫度分佈等物理現象。

The phenomena of Coulomb explosion require the consideration of special relativity due to the involvement of high-energy electrons or ions. It is known that laser ablation processes at high laser intensities may lead to such the Coulomb explosion, and their released energy is in the regime of kilo to mega eV. In contrast to conventional molecular dynamics (MD) simulations, we adopt the three-dimensional relativistic molecular dynamics (RMD) method to consider the effects of special relativity in the conventional MD simulation for charged particles in strong electromagnetic fields. Furthermore, we develop a Coulomb force scheme, combining with the Lennard-Jones potential, to calculate interactions between charged particles, and adopt a Verlet list scheme to compute the interactions between each particle. The energy transfer from the laser pulses to the solid surface is not directly simulated. In stead, we directly assign ion charges to the surface atoms that are illuminated by the laser. By introducing the Coulomb potential into the Lennard-Jones potential, we are able to mimic the laser energy being dumped into the Xe solid, and track the motion of each Xe atoms. In other words, the laser intensity is simulated by using the repulsive forces from the Coulomb potential. Both non-relativistic and relativistic simulations are performed, and the RMD method provides more realistic results, in particular, when high-intensity laser is used. In addition, it is found that the damage depth does not increase with repeated laser ablation when the pulse frequency is comparable to the duration of the pulse. Furthermore, we report the time evolution of energy propagation in space in the laser ablation process. The temporal-spatial distribution of energy indirectly indicates the temperature evolution on the surface of the Xe solid under intense laser illumination.

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