Fingerprints of energy dissipation for exothermic surface chemical reactions: O2 on Pd(100).
Fingerprints of energy dissipation for exothermic surface chemical reactions: O2 on Pd(100).
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DOI：
10.1063/1.4926989
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发表时间：
2015-06
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影响因子：
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通讯作者：
Vanessa J. Bukas;Shubhrajyoti Mitra;Jörg Meyer;K. Reuter
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文献类型：
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作者：
Vanessa J. Bukas;Shubhrajyoti Mitra;Jörg Meyer;K. Reuter
我们提出了第一性原理计算的吸附系数的O2在Pd（100），以评估声子能量耗散对这个动力学参数的影响。为此，我们增加了六维势能面（PES）的动态模拟代表分子的自由度与各种有效的帐户表面流动性。在比较流行的冻结表面的方法，能量耗散被发现定性地影响所计算的粘附曲线。在广义Langevin振子模型的水平上，我们取得了很好的协议与实验数据。协议同样达成了基于两个不同的半局部密度泛函理论泛函的PES。模拟粘附曲线的这种稳健性不延伸到潜在的吸附机制，其主要是直接解离一个功能或分子捕获的其他。完全不同的吸附机制，从而导致相当相似的粘附曲线，同意同样好的实验数据。这突出了普遍做法的危险性，即从这种放热表面反应的测量粘附数据的简单指纹中提取相应的机械细节。
We present first-principles calculations of the sticking coefficient of O2 at Pd(100) to assess the effect of phononic energy dissipation on this kinetic parameter. For this, we augment dynamical simulations on six-dimensional potential energy surfaces (PESs) representing the molecular degrees of freedom with various effective accounts of surface mobility. In comparison to the prevalent frozen-surface approach, energy dissipation is found to qualitatively affect the calculated sticking curves. At the level of a generalized Langevin oscillator model, we achieve good agreement with experimental data. The agreement is similarly reached for PESs based on two different semi-local density-functional theory functionals. This robustness of the simulated sticking curve does not extend to the underlying adsorption mechanism, which is predominantly directly dissociative for one functional or molecularly trapped for the other. Completely different adsorption mechanisms therewith lead to rather similar sticking curves that agree equally well with the experimental data. This highlights the danger of the prevalent practice to extract corresponding mechanistic details from simple fingerprints of measured sticking data for such exothermic surface reactions.