Kinetic Barriers of the Phase Transition in the Oxygen Chemisorbed Cu(110)-(2 x 1)-O as a Function of Oxygen Coverage
Kinetic Barriers of the Phase Transition in the Oxygen Chemisorbed Cu(110)-(2 x 1)-O as a Function of Oxygen Coverage
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DOI：
10.1021/jp503757k
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发表时间：
2014-09-11
影响因子：
3.7
通讯作者：
Zhou, Guangwen
中科院分区：
文献类型：
--
作者：
Li, Liang;Liu, Qianqian;Zhou, Guangwen
氧化学吸附引起的表面重构被广泛观察到，但导致氧化学吸附相之间转变的原子过程在很大程度上是未知的。利用从头算分子动力学和密度泛函理论，研究了氧表面覆盖度增加时，Cu(110)-(2×1)-&Gt；c(6×2)相变的动力学过程。结果表明，这一相变首先是由动能垒约为0.13 eV的Cu-O二聚体和三聚体的形成，然后是一个无障碍的形成四个Cu-O-Cu-O链构型的过程，该构型通过三个铜原子的协同运动转变为c(6×2)重构，相应的能垒约为1.41 eV。从实验观察到的(2×1)->；c(6×2)相变与平衡热力学预测的显著差异推测，较大的动能垒是动力学势垒的来源。
Oxygen chemisorption induced surface reconstructions are widely observed, but the atomic processes leading to transitions among oxygen chemisorbed phases are largely unknown. Using ab initio molecular dynamics and density-functional theory, we study the kinetic process of the Cu(110)-(2 x 1) -> c(6 x 2) phase transition upon increasing oxygen surface coverage. We show that the phase transition involves initially Cu-O dimer and Cu-O-Cu trimer formation with a kinetic barrier of similar to 0.13 eV, followed by a barrierless process of forming a four Cu-O-Cu-O chains configuration that transitions to the c(6 x 2) reconstruction via concerted movement of three Cu atoms with an associated energy barrier of similar to 1.41 eV. The larger kinetic barrier is suggested as the origin of the kinetic hindrance that is inferred from the significant discrepancy between the experimentally observed temperature and pressure dependent (2 x 1) -> c(6 x 2) phase transition and the equilibrium thermodynamics prediction.