Cheng Yu-Ting, Shan Tzu-Ray, Liang Tao, Behera Rakesh K, Phillpot Simon R, Sinnott Susan B
Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611-6400, USA.
J Phys Condens Matter. 2014 Aug 6;26(31):315007. doi: 10.1088/0953-8984/26/31/315007. Epub 2014 Jun 19.
This work proposes an empirical, variable charge potential for Ti and TiO(2) systems based on the charge-optimized many-body (COMB) potential framework. The parameters of the potential function are fit to the structural and mechanical properties of the Ti hcp phase, the TiO(2) rutile phase, and the energetics of polymorphs of both Ti and TiO(2). The relative stabilities of TiO(2) rutile surfaces are predicted and compared to the results of density functional theory (DFT) and empirical potential calculations. The transferability of the developed potential is demonstrated by determining the adsorption energy of Cu clusters of various sizes on the rutile TiO(2)(1 1 0) surface using molecular dynamics simulations. The results indicate that the adsorption energy is dependent on the number of Cu-Cu bonds and Cu-O bonds formed at the Cu/TiO(2) interface. The adsorption energies of Cu clusters on the reduced and oxidized TiO(2)(1 1 0) surfaces are also investigated, and the COMB potential predicts enhanced bonding between Cu clusters and the oxidized surface, which is consistent with both experimental observations and the results of DFT calculations for other transition metals (Au and Ag) on this oxidized surface.
这项工作基于电荷优化多体（COMB）势框架，为钛（Ti）和二氧化钛（TiO₂）体系提出了一种经验性可变电荷势。势函数的参数与Ti六方密堆积相、TiO₂金红石相的结构和力学性能以及Ti和TiO₂多晶型体的能量学进行了拟合。预测了TiO₂金红石表面的相对稳定性，并与密度泛函理论（DFT）和经验势计算结果进行了比较。通过使用分子动力学模拟确定不同尺寸的铜（Cu）团簇在金红石TiO₂（1 1 0）表面的吸附能，证明了所开发势的可转移性。结果表明，吸附能取决于在Cu/TiO₂界面形成的Cu-Cu键和Cu-O键的数量。还研究了Cu团簇在还原和氧化的TiO₂（1 1 0）表面上的吸附能，COMB势预测Cu团簇与氧化表面之间的键合增强，这与实验观察结果以及其他过渡金属（Au和Ag）在该氧化表面上的DFT计算结果一致。
