Role of substrate excitation in the photochemistry of dioxygen on Ag(110)
Role of substrate excitation in the photochemistry of dioxygen on Ag(110)
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底物激发在 Ag(110) 上双氧光化学中的作用
DOI：
10.1116/1.578003
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
A. Campion
中科院分区：
文献类型：
--
作者：
S. R. Hatch;A. Campion
利用程序升温解吸和高分辨率电子能量损失光谱测量了 UV 照射下 Ag(110) 上 O2 光解离和光解吸的速率。吸附在 Ag(110) 上的 O2 的排列允许在法向入射下进行偏振测量。发现该速率与光电场的方位角方向无关。对入射角的依赖性与菲涅尔方程预测的金属吸收的角度依赖性一致。这些观察结果排除了直接的吸附质内激发，并提出了底物介导的机制。相似的光激发阈值表明这两个通道是由共同的过程激活的。提出了一种模型，通过该模型底物电荷转移引起解离。离解的吸附原子与分子氧竞争吸附位点，引起分子解吸。该模型再现了两个通道对初始 O2 覆盖范围和照射程度的依赖性......
The rates of O2 photodissociation and photodesorption on Ag(110) under UV irradiaton have been measured with temperature programmed desorption and high‐resolution electron energy loss spectroscopy. The alignment of O2 adsorbed on Ag(110) permits polarization measurements at normal incidence. The rates are found to be independent of the azimuthal orientation of the electric field of the light. Dependences on angle of incidence are consistent with the angle dependence of metal absorption predicted by Fresnel’s equations. These observations rule out direct intra‐adsorbate excitation and suggest a substrate mediated mechanism. Similar photoexcitation thresholds suggest that both channels are activated by a common process. A model is proposed whereby substrate charge transfer induces dissociation. Dissociating adatoms, in competition with molecular oxygen for adsorption sites, induce molecular desorption. This model reproduces the dependences on initial O2 coverage and extent of irradiation for both channels a...