Nakamura Hisao, Yamashita Koichi
Department of Chemical System Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
J Chem Phys. 2006 Aug 28;125(8):084708. doi: 10.1063/1.2338027.
The photoinduced desorption of NO molecules on a Ag surface was studied theoretically using a recently developed method based on the nonequilibrium Green's function approach combined with the density functional theory. Geometry optimizations for the stable NO dimer phase were carried out, and two structures of adsorbed dimers were identified. We calculated the reaction probabilities as a function of incident photon energy for each of the dimers and compared them with experimental action spectra. The two main features of the action spectra, (i) a long tail to the long wavelength (approximately 600 nm) and (ii) a rapid increase at approximately 350 nm, were well reproduced. By theoretical analysis, we found the importance of quantum interference for the interfacial charge transfer between the metal substrate and the adsorbate, as well as the contribution of secondary electrons. Our calculations suggest that the photoactive species is dimeric and that the resonant level is single for the photodesorption of NO.
采用最近基于非平衡格林函数方法与密度泛函理论相结合发展的一种方法，对银表面上一氧化氮（NO）分子的光致脱附进行了理论研究。对稳定的NO二聚体相进行了几何优化，并确定了吸附二聚体的两种结构。我们计算了每个二聚体的反应概率作为入射光子能量的函数，并将其与实验光电流谱进行了比较。光电流谱的两个主要特征，（i）长波长（约600nm）处的长尾，以及（ii）约350nm处的快速增加，都得到了很好的再现。通过理论分析，我们发现了量子干涉对金属基底与吸附质之间界面电荷转移的重要性，以及二次电子的贡献。我们的计算表明，光活性物种是二聚体，并且对于NO的光脱附，共振能级是单一的。
