Wagner Roman J V, Henning Niklas, Krüger Bastian C, Park G Barratt, Altschäffel Jan, Kandratsenka Alexander, Wodtke Alec M, Schäfer Tim
University of Goettingen , Institute of Physical Chemistry, Tammannstraße 6, 37077 Goettingen, Germany.
Department of Dynamics at Surfaces, Max-Planck-Institute for Biophysical Chemistry , Am Faßberg 11, 37077 Goettingen, Germany.
J Phys Chem Lett. 2017 Oct 5;8(19):4887-4892. doi: 10.1021/acs.jpclett.7b02207. Epub 2017 Sep 26.
Electronically nonadiabatic dynamics can be important in collisions of molecules at surfaces; for example, when vibrational degrees of freedom of molecules are coupled to electron-hole-pair (EHP) excitation of a metal. Such dynamics have been inferred from a host of observations involving multiquantum relaxation of NO molecules scattered from metal surfaces. Electron transfer forming transient NO is thought to be essential to the nonadiabatic coupling. The question remains: is this behavior usual? Here, we present final vibrational state distributions resulting from the scattering of CO(v = 17) from Au(111), which exhibits significantly less vibrational relaxation than NO(v = 16). We explain this observation in terms of the lower electron affinity of CO compared to NO, a result that is consistent with the formation of a transient CO ion being important to CO vibrational relaxation.
电子非绝热动力学在分子与表面的碰撞中可能很重要；例如，当分子的振动自由度与金属的电子 - 空穴对（EHP）激发耦合时。这种动力学已从大量涉及从金属表面散射的NO分子的多量子弛豫的观察中推断出来。形成瞬态NO的电子转移被认为是非绝热耦合的关键。问题仍然存在：这种行为常见吗？在这里，我们展示了CO（v = 17）从Au（111）表面散射后产生的最终振动态分布，其振动弛豫比NO（v = 16）显著更少。我们根据CO与NO相比更低的电子亲和能来解释这一观察结果，这一结果与形成对CO振动弛豫很重要的瞬态CO离子是一致的。
