Gomez Maria A, Jindal Saryu, Fletcher Katharyn M, Foster Leigh S, Addo Nanna Dufie A, Valentin Debbie, Ghenoiu Cristina, Hamilton Abigail
Department of Chemistry, Mount Holyoke College, South Hadley, Massachusetts 01075, USA.
J Chem Phys. 2007 May 21;126(19):194701. doi: 10.1063/1.2735592.
In the present paper, the authors focus on proton conduction pathways in a cubic perovskite KTaO(3) and an orthorhombic perovskite SrZrO(3). Density functional theory with a generalized gradient approximation is used to find proton binding sites. The nudged elastic band method is used to find transition states between minima. With this potential energy map of binding and transition states, adjacency matrices and their analogs identify four types of conduction paths in KTaO(3). Distortions from these paths are seen in SrZrO(3). In both cases, the lowest energy path has an intraoctahedral transfer rate-limiting barrier. A Fourier analysis of the OH stretch in ab initio molecular dynamics simulations revealed a strongly redshifted OH stretch in SrZrO(3) relative to KTaO(3). Hence, an orthorhombic system with a lowest energy conduction path limited by an intraoctahedral barrier can exhibit a redshifted OH stretch.
在本文中，作者聚焦于立方钙钛矿KTaO₃和正交钙钛矿SrZrO₃中的质子传导路径。采用广义梯度近似的密度泛函理论来寻找质子结合位点。使用推挤弹性带方法来寻找极小值之间的过渡态。利用这种结合态和过渡态的势能图，邻接矩阵及其类似物确定了KTaO₃中的四种传导路径类型。在SrZrO₃中可以看到偏离这些路径的畸变。在这两种情况下，能量最低的路径都具有八面体内转移速率限制势垒。在从头算分子动力学模拟中对OH伸缩振动的傅里叶分析表明，相对于KTaO₃，SrZrO₃中的OH伸缩振动发生了强烈的红移。因此，具有由八面体内势垒限制的能量最低传导路径的正交晶系可以表现出OH伸缩振动的红移。
