We investigated the effects of paramagnetic (PM) fluctuations on the thermochemistry of the MnO(100) surface in the oxygen evolution reaction (OER) using the “noncollinear magnetic sampling method plus U” (NCMSM+U). Various physical properties, such as the electronic structure, free energy, and charge occupation, of the MnO(100) surface in the PM state with several OER intermediates, were reckoned and compared to those in the antiferromagnetic (AFM) state. We found that PM fluctuation enhances charge transfer from a surface Mn ion to each of the intermediates and strengthens the chemical bond between them, while not altering the overall features, such as the rate determining step and resting state, in reaction pathways. The enhanced charge transfer can be attributed to the delocalized nature of valence bands observed in the PM surface. In addition, it was observed that chemical-bond enhancement depends on the intermediates, resulting in significant deviations in reaction energy barriers. Our study suggests that PM fluctuations play a significant role in the thermochemistry of chemical reactions occurring on correlated oxide surfaces.

中文翻译：

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顺磁涨落对氧析出反应中MnO（100）表面热化学的影响

我们使用“非共线磁性采样方法加U ”（NCMSM + U）研究了顺磁（PM）波动对氧释放反应（OER）中MnO（100）表面热化学的影响）。推算出具有几种OER中间体的PM状态下MnO（100）表面的各种物理性质，如电子结构，自由能和电荷占用，并将其与反铁磁（AFM）状态进行了比较。我们发现，PM波动增强了从表面Mn离子到每个中间体的电荷转移，并增强了它们之间的化学键，同时不改变反应路径中的总体特征，如速率确定步骤和静止状态。增强的电荷转移可归因于在PM表面观察到的价带的离域性质。另外，观察到化学键的增强取决于中间体，导致反应能垒的显着偏离。