Gerrits Nick, Geweke Jan, Auerbach Daniel J, Beck Rainer D, Kroes Geert-Jan
Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry, Göttingen, Am Fassberg 11, 37077 Göttingen, Germany.
J Phys Chem Lett. 2021 Aug 5;12(30):7252-7260. doi: 10.1021/acs.jpclett.1c02093. Epub 2021 Jul 27.
The probability for dissociation of molecules on metal surfaces, which often controls the rate of industrially important catalytic processes, can depend strongly on how energy is partitioned in the incident molecule. There are many example systems where the addition of vibrational energy promotes reaction more effectively than the addition of translational energy, but for rotational pre-excitation similar examples have not yet been discovered. Here, we make an experimentally testable theoretical prediction that adding energy to the rotation of HCl can promote its dissociation on Au(111) 20 times more effectively than increasing its translational energy. In the underlying mechanism, the molecule's initial rotational motion allows it to pass through a critical region of the reaction path, where this path shows a strong and nonmonotonic dependence on the molecular orientation.
分子在金属表面解离的概率通常控制着工业上重要催化过程的速率，它可能强烈依赖于入射分子中能量的分配方式。在许多示例系统中，添加振动能比添加平动能更有效地促进反应，但对于转动预激发，尚未发现类似的示例。在这里，我们做出了一个可通过实验验证的理论预测：给HCl分子的转动添加能量比增加其平动能能更有效地促进其在Au(111)表面的解离，效率要高出20倍。在潜在机制中，分子的初始转动运动使其能够通过反应路径的一个关键区域，在该区域中，反应路径对分子取向呈现出强烈的非单调依赖性。
