Sn的分析型键级势

Analytical bond-order potential for Sn

基于类似于Tersoff-Brenner模型的键级势架构,从Sn的5种几何构型的基本物性第一性原理计算结果和实验结果出发,通过Levenberg-Marquardt方法建立了Sn的分析型键级势.利用得到的相互作用势和分子动力学方法,计算了Sn的β相和体心四方晶体相的晶体结构、结合能、键距、键能以及体变模量,并进而计算了Sn的α和β相的自由能、内能和熵随温度的变化.结果表明,β相和体心四方晶体相的基本物性以及αβ相变温度计算结果与实验值符合良好,建立的分析型键级势可用于Sn基钎料合金性质的大尺度分子动力学模拟.

An analytical bond-order potential based on Tersoff-Brenner model for Sn is developed using the Levenberg-Marquardt opti- mization algorithm with the first-principles calculations on fundamental physical properties of five configurations of Sn, and with the available experimental results. The potential is used to determine the crystal structures, binding energies, bond distances and strengths, and bulk modulus of the fl-Sn and body-centered-tetragonal Sn, and to predict the changes in free energy of the a and fl phase with temperature. Result indicate that the calculated basic properties of the phases and the predicted transition temperature from ct to fl phase are in good agreement with the reported experimental data. The proposed interatomic potential is short-ranged and quickly eval- uated, and it could be used to distinguish covalent bond from metallic bond in the phases, so it is very useful for large-scale molecular dynamics simulations of Sn-based solder.