Anisotropy of Shear-Induced Mechanochemical Reaction Rates of Surface Adsorbates; Implications for Theoretical Models
Anisotropy of Shear-Induced Mechanochemical Reaction Rates of Surface Adsorbates; Implications for Theoretical Models
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表面吸附物剪切诱导的机械化学反应速率的各向异性；
DOI：
10.1021/acs.jpcc.2c03033
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Tysoe, Wilfred T.
中科院分区：
文献类型：
--
作者：
Rana, Resham;Djuidje Kenmoe, Germaine;Sidoroff, François;Bavisotto, Robert;Hopper, Nicholas;Tysoe, Wilfred T.
机械化学反应通过施加力来改变并理想地加速机械活性物质（机械载体）的反应速率而发生。热反应由势能面（PES）从过渡态到反应物态的最陡下降路径（SDP）描述，它们是SDP上的驻点。活化能由这两点之间的能量差计算。PES通过施加力进行修改，以产生由力位移固定点（FDSP）给出的反应途径，这取决于力的大小和方向以及PES的形状。然而，SDP在垂直于它的方向上的力为零，因此PES可以被视为“谐波谷”，其在SDP周围形成势能谷。如果势槽的壁足够陡峭，则机械化学反应应被限制为沿着SDP发生，并且所施加的力的影响应仅取决于力沿着SDP的分量。如果是这种情况，应该可以仅使用初始和过渡态周围的PES的形状来计算施加的力或应力对机械化学反应速率的影响。通过改变原子力显微镜尖端在Cu（100）单晶表面上的滑动方向，测量机械化学甲基硫醇盐分解速率的方位角依赖性，对吸附在Cu（100）单晶表面上的甲基硫醇盐物质的机械诱导分解进行了检验。该概念还使用使用Remoissenet-Peyrard函数模拟Cu（100）表面的电势的模型4倍电势来说明。这就产生了与上述假设的预测相一致的角度依赖性。这种简化将有助于分析表面和本体反应的机械化学速率。
Mechanochemical reactions occur by an applied force modifying and ideally accelerating the rate of reaction of a mechanically active species, a mechanophore. Thermal reactions are described by the steepest descent pathway (SDP) of the potential energy surface (PES) from the transition state to the reactant state, which are stationary points on the SDP. The activation energy is calculated from the energy difference between these two points. The PES is modified by an imposed force to yield a reaction pathway given by the force-displaced stationary points (FDSPs), which depend on the magnitude and direction of the force and shape of the PES. However, the SDP has zero force in a direction perpendicular to it so that the PES can be visualized as a “harmonic valley” that forms a potential energy trough about the SDP. If the walls of the potential trough are sufficiently steep, a mechanochemical reaction should be constrained to occur along the SDP, and the influence of an applied force should depend only on the component of the force along it. If this is the case, it should be possible to use just the shape of the PES around the initial and transition states to calculate the effect of an imposed force or stress on mechanochemical reaction rates. The postulate is tested for the mechanically induced decomposition of an adsorbed methyl thiolate species on a Cu(100) single-crystal surface by measuring the azimuthal angular dependence of the mechanochemical methyl thiolate decomposition rate by varying the sliding direction of a sharp atomic force microscope tip over the surface in ultrahigh vacuum. The concept is also illustrated using a model 4-fold potential using a Remoissenet–Peyrard function to mimic the potential of a Cu(100) surface. This yields an angular dependence that agrees well with the prediction from the above postulate. This simplification will facilitate the analysis of mechanochemical rates of both surface and bulk reactions.
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影响因子：
2.9
作者：
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影响因子：
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影响因子：
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作者：
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作者：
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