液態鉛的動力學性質研究

Abstract

本篇論文致力於利用分子動力模擬及瞬間正則模探討液態鉛的各項動力學性質，文中分別探討兩種不同理論基礎的虛擬液態鉛位能，並比較一系列的動力學性質結果以了解兩者的差異，包括粒子徑向分布函數、靜態結構因子、動態結構因子、粒子速度相干函數、瞬間正則模態密度以及參與比例，並試圖尋找瞬間共振模，最後的結論為如果在虛擬液態鉛位能中的核心排斥力部分有反曲點的話，就可以發現瞬間共振模的存在，且瞬間共振模的態密度分布會隨著溫度的升高而增加。

The main purpose of this thesis is to explore several dynamic properties of liquid Pb, using the molecule dynamic simulation and the instantaneous normal mode analysis. Two potentials of liquid Pb based on different theories are discussed, and the results of their dynamic properties, including radial distribution function, static structure factor, dynamic structure factor, velocity autocorrelation function, density of state and participation ratio, are compared in order to investigate the differences. Attempt is also made to find out the instantaneous resonant modes in liquid Pb in this study. It is concluded that the existence of instantaneous resonant modes can be found in the case that there is a reflection point in the repulsive core of the liquid Pb potential. It is found out that the density of states of instantaneous resonant mode increases with the increase of temperature.