Shuai Quan, Kaufmann Sven, Auerbach Daniel J, Schwarzer Dirk, Wodtke Alec M
Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry , Am Faßberg 11, 37077 Göttingen, Germany.
Institute for Physical Chemistry, Georg-August University of Goettingen , Tammannstraße 6, 37077 Göttingen, Germany.
J Phys Chem Lett. 2017 Apr 6;8(7):1657-1663. doi: 10.1021/acs.jpclett.7b00265. Epub 2017 Mar 27.
The dissociative adsorption reaction of hydrogen on noble metals is believed to be well-described within the Born-Oppenheimer approximation. In this work, we have experimentally derived translational energy distributions for selected quantum states of H and D formed in associative desorption reactions at a Au(111) surface. Using the principle of detailed balance, we compare our results to theory carried out at the same level of sophistication as was done for the reaction on copper. The theory predicts translational excitation that is much higher than is seen in experiment and fails to reproduce the experimentally observed isotope effect. The large deviations between experiment and theory are surprising because, for the same reactions occurring on Cu(111), a similar theoretical strategy agreed with experiment, yielding "chemical accuracy". We argue that electron-hole pair excitation is more important for the reaction on gold, an effect that may be related to the reaction's later transition state.
氢在贵金属上的解离吸附反应被认为在玻恩-奥本海默近似下能得到很好的描述。在这项工作中，我们通过实验得出了在金（111）表面的缔合脱附反应中形成的选定H和D量子态的平动能分布。利用细致平衡原理，我们将我们的结果与在与铜表面反应相同复杂程度水平上进行的理论计算进行比较。该理论预测的平动激发比实验中观察到的要高得多，并且无法重现实验观察到的同位素效应。实验与理论之间的巨大偏差令人惊讶，因为对于在铜（111）上发生的相同反应，类似的理论策略与实验结果相符，达到了“化学精度”。我们认为电子-空穴对激发对金表面的反应更为重要，这种效应可能与反应较晚的过渡态有关。
