Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, United States.
J Phys Chem A. 2011 Dec 22;115(50):14306-14. doi: 10.1021/jp205868g. Epub 2011 Nov 23.
We report kinetic energy distributions of exoelectrons produced by collisions of highly vibrationally excited NO molecules with a low work function Cs dosed Au(111) surface. These measurements show that energy dissipation pathways involving nonadiabatic conversion of vibrational energy to electronic energy can result in electronic excitation of more than 3 eV, consistent with the available vibrational energy. We measured the dependence of the electron energy distributions on the translational and vibrational energy of the incident NO and find a clear positive correlation between final electron kinetic energy and initial vibrational excitation and a weak but observable inverse dependence of electron kinetic energy on initial translational energy. These observations are consistent with a vibrational autodetachment mechanism, where an electron is transferred to NO near its outer vibrational turning point and ejected near its inner vibrational turning point. Within the context of this model, we estimate the NO-to-surface distance for electron transfer.
我们报告了由高振动激发的 NO 分子与 Cs 剂量的低功函数 Au(111)表面碰撞产生的外电子的动能分布。这些测量表明，涉及非绝热转换振动能量到电子能量的能量耗散途径可能导致超过 3 eV 的电子激发，这与可用的振动能量一致。我们测量了电子能量分布对入射 NO 的平动和振动能量的依赖性，并发现最终电子动能与初始振动激发之间存在明显的正相关关系，并且电子动能对初始平动能量的依赖关系虽然较弱但可观察到。这些观察结果与振动自脱附机制一致，其中电子转移到靠近其外部振动转折点的 NO 并在其内部振动转折点附近被逐出。在这个模型的背景下，我们估计了电子转移到 NO 到表面的距离。
