Damping of molecular motion on a solid substrate: Evidence for electron-hole pair creation
Damping of molecular motion on a solid substrate: Evidence for electron-hole pair creation
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DOI：
10.1103/physrevlett.80.121
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发表时间：
1998-01-05
影响因子：
8.6
通讯作者：
Woll, C
中科院分区：
文献类型：
--
作者：
Witte, G;Weiss, K;Woll, C
利用高分辨率振动光谱技术研究了分子相对于固体基底的运动阻尼。对于吸附在氢钝化Ru（0001）表面上的辛烷，通过he原子散射观察到的与表面垂直的受挫平移的实验线宽与声子发射的阻尼一致，但在干净的Ru衬底上发现了强展宽。这种增强的摩擦与电子-空穴（e-h）对产生速率的增加有关，这是由于氢钝化表面不存在的杂化金属-分子电子态的存在。近边x射线吸收光谱的数据为这些电子结构的差异提供了直接证据。红外光谱结果有力地表明，在这些体系中观测到的软C-H波段也与这些杂化电子态的形成有关。
The damping of molecular motion relative to a solid substrate was investigated by high-resolution vibrational spectroscopy in the far-infrared regime. For octane adsorbed on a hydrogen-passivated Ru(0001) surface the experimental linewidths observed by He-atom scattering for the frustrated translation normal to the surface are in accord with a damping by phonon emission, but a strong broadening is found for the clean Ru substrate. This enhanced friction is related to an-increase in the rate of electron-hole (e-h) pair creation due to the presence of hybrid metal-molecule electronic states which are absent for the hydrogen passivated surface. Data from near-edge x-ray absorption spectroscopy provide direct evidence for these differences in electronic structure. Results from IR spectroscopy strongly suggest that the soft C-H bands observed for these systems are also related to the formation of these hybrid electronic states.