Coherent quantum scattering of CH4 from Ni(111)
Coherent quantum scattering of CH4 from Ni(111)
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DOI：
10.1039/c7cp04559j
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发表时间：
2017-08-28
影响因子：
3.3
通讯作者：
Farias, Daniel
中科院分区：
文献类型：
--
作者：
Al Taleb, Amjad;Farias, Daniel
我们测量了入射能量在68.9 meV和108.6 meV之间的甲烷从Ni（111）表面散射的高分辨率角分布。除了沿着Ni（111）的两个主要对称方向的对应于旋转非弹性衍射（RID）峰的尖锐特征之外，还观察到尖锐且强烈的镜面反射峰。最强烈的RID峰的强度约为。镜面反射的50%。在如此低的入射能量下观察到尖锐的、相干的弹性峰表明，在这些能量下，单次散射在捕获上占主导地位，并且货车德瓦尔斯阱的深度应低于60 meV。相反，在相同的入射条件下，从石墨烯覆盖的Ni（111）表面观察到从镜面位置偏移的宽角分布。这些结果开辟了使用高分辨率分子束研究CH 4和过渡金属表面之间的物理吸附的可能性。
We have measured high-resolution angular distributions of methane scattered from a Ni(111) surface at incident energies between 68.9 meV and 108.6 meV. A sharp and intense specular peak has been observed, in addition to sharp features corresponding to rotationally inelastic diffraction (RID) peaks along the two main symmetry directions of Ni(111). The intensity of the most intense RID peaks is ca. 50% of the specular one. The observation of sharp, coherent elastic peaks at such low incident energies suggests that single scattering dominates over trapping at these energies, and that the depth of the van der Waals well should be lower than 60 meV. In contrast, a broad angular distribution shifted from the specular position is observed from a graphene-covered Ni(111) surface under identical incident conditions. These results open up the possibility of studying the physisorption well between CH4 and a transition metal surface using high-resolution molecular beams.