Using the reaction–diffusion model for hydrogen (H) trapping in spherical cavities in metals (Zibrov and Schmid, 2022), we theoretically analyze the case of H trapping only in chemisorption sites at the cavity surface. We show that the model can be reduced to a form that is similar to the conventional model of H trapping in point defects. The reduced model includes analytical expressions for correction factors to account for correlated H retrapping by the same cavity and inhomogeneous H potential energy landscape in the vicinity of the cavity surface. We show that these correction factors play a significant role in thermal desorption (TDS) simulations only in the case of very low cavity number densities (detrapping-limited regime), which is rarely encountered in experiments.

中文翻译：

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金属球形空腔中增强氢捕获的因素

使用金属球形空腔中氢 (H) 捕获的反应扩散模型（Zibrov 和 Schmid，2022），我们从理论上分析了仅在空腔表面的化学吸附位点捕获 H 的情况。我们证明该模型可以简化为类似于点缺陷中 H 捕获的传统模型的形式。简化模型包括校正因子的解析表达式，以解释同一腔体的相关 H 重捕获以及腔表面附近的不均匀 H 势能景观。我们表明，这些校正因子仅在空腔数密度非常低（去捕获限制范围）的情况下在热解吸（TDS）模拟中发挥重要作用，这在实验中很少遇到。