Force Field Parameter Development for the Thiolate/Defective Au(111) Interface
Force Field Parameter Development for the Thiolate/Defective Au(111) Interface
复制标题
硫醇盐/缺陷 Au(111) 界面的力场参数开发
DOI：
10.1021/acs.langmuir.0c00530
复制
发表时间：
2020
期刊：
影响因子：
3.9
通讯作者：
Huang Liangliang
中科院分区：
文献类型：
--
作者：
Zhou Guobing;Liu Chang;Bumm Lloyd A.;Huang Liangliang
从分子水平理解硫醇盐自组装膜与金表面的相互作用对表面科学和纳米技术的广泛应用具有重要意义。尽管在过去的十年里，理论研究取得了进展，一个原子模型，能够描述的自组装膜在重建的金表面的关键特征，仍然是失踪。本工作利用周期性从头计算密度泛函理论（DFT）建立了一个新的原子力场模型，研究了烷基硫醇（AT）在重构Au（111）表面的自组装行为.仔细训练新的力场参数以再现关键特征，包括Au（111）表面上的桥或钉合模体模型中乙硫醇（C2 S）的振动光谱和扭转能分布，其中，通过匹配振动光谱来训练键项和角项的力常数，而二面角的扭转参数通过拟合DFT计算的扭转能分布来训练。为了验证开发的力场参数，我们进行了经典的分子动力学（MD）模拟的原始和重建的Au-S界面模型与（2根3）的晶胞，其中包括四个十二硫醇（C10 S）分子的Au（111）表面。模拟结果表明，所研究的Au-S界面模型的几何特征和C10 S自组装膜的结构特性与从头算分子动力学研究结果吻合较好。新发展的原子力场模型提供了新的基本见解，在重建的Au（111）表面的AT自组装膜，并增加了现有的界面研究知识的进步。
A molecular-level understanding of the interplay between self-assembled monolayers (SAMs) of thiolates and gold surface is of great importance to a wide range of applications in surface science and nanotechnology. Despite theoretical research progress of the past decade, an atomistic model, capable of describing key features of SAMs at reconstructed gold surfaces, is still missing. In this work, periodic ab initio density functional theory (DFT) calculations were utilized to develop a new atomistic force field model for alkanethiolate (AT) SAMs on a reconstructed Au(111) surface. The new force field parameters were carefully trained to reproduce the key features, including vibrational spectra and torsion energy profiles of ethylthiolate (C2S) in the bridge or staple motif model on the Au(111) surface, wherein, the force constants of the bond and angle terms were trained by matching the vibrational spectra, while the torsion parameters of the dihedral angles were trained via fitting the torsion energy profiles from DFT calculations. To validate the developed force field parameters, we performed classical molecular dynamics (MD) simulations for both pristine and reconstructed Au-S interface models with a (2 root 3) unit cell, which includes four dodecanethiolate (C10S) molecules on the Au(111) surface. The simulation results showed that the geometrical features of the investigated Au-S interface models and structural properties of the C10S SAMs are in good agreement with the ab initio MD studies. The newly developed atomistic force field model provides new fundamental insights into AT SAMs on the reconstructed Au(111) surface and adds advancement to the existing interface research knowledge.