Graduate School of Pure and Applied Science, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8573, Japan.
J Phys Chem A. 2011 Jun 30;115(25):7089-95. doi: 10.1021/jp112394m. Epub 2011 Mar 29.
The scattering of the oxygen molecule from a graphite surface has been studied using a molecular beam scattering technique. The angular intensity distributions of scattered oxygen molecules were measured at incident energies from 291 to 614 meV with surface temperatures from 150 to 500 K. Every observed distribution has a single peak at a larger final angle than the specular angle of 45° which indicates that the normal component of the translation energy of the oxygen molecule is lost by the collision with the graphite surface. The amount of the energy loss by the collision has been roughly estimated as about 30-41% based on the assumption of the tangential momentum conservation during the collision. The distributions have also been analyzed with two theoretical models, the hard cubes model and the smooth surface model. These results indicate that the scattering is dominated by a single collision event of the particle with a flat surface having a large effective mass. The derived effective mass of the graphite surface for the incoming oxygen is 9-12 times heavier than that of a single carbon atom, suggesting a large cooperative motion of the carbon atoms in the topmost graphene layer.
利用分子束散射技术研究了氧气分子从石墨表面的散射。在表面温度为 150 至 500 K 的条件下，测量了入射能量为 291 至 614 meV 的散射氧气分子的角强度分布。每个观察到的分布在比 45°镜面角更大的最终角度处只有一个峰，这表明氧气分子的平移能量的法向分量在与石墨表面的碰撞中损失。根据碰撞过程中切向动量守恒的假设，大致估计了碰撞引起的能量损失约为 30-41%。这些分布也用两个理论模型，硬立方模型和光滑表面模型进行了分析。这些结果表明，散射主要由与具有大有效质量的平面的单次碰撞事件主导。对于入射氧，石墨表面的推导有效质量是单个碳原子的 9-12 倍，表明最顶层石墨烯层中碳原子的协同运动很大。
