Surface temperature dependence of the steric effect in the scattering of oriented tert‐butyl chloride and fluoroform molecules by graphite(0001)
Surface temperature dependence of the steric effect in the scattering of oriented tert‐butyl chloride and fluoroform molecules by graphite(0001)
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石墨(0001)定向叔丁基氯和氟仿分子散射中空间效应的表面温度依赖性
DOI：
10.1063/1.459415
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
R. Bernstein
中科院分区：
文献类型：
--
作者：
S. Ionov;Michael E. Lavilla;R. S. Mackay;R. Bernstein
研究了石墨（0001）表面温度范围为165 < Ts<730 K的六极取向t - bul和CHF3分子聚焦光束的散射。比较了分子偶极子的平行和反平行入射方向相对于表面法线的表面散射光束的检测数密度。从散射信号的分数差，即所谓的空间效应，以及从无取向分子的散射角分布，可以得到相反分子取向的散射概率的相对差异。对于这两种分子，散射的相对差值（位阻效应）的大小随着Ts的减小而增大。在165 K的最低表面温度下，t‐bul的散射概率的相对差值达到+1.5 (CHF3为- 0.8)，接近最大可能的2.0量级，而在最高温度下，散射概率的相对差值为+0.3 （CHF3为- 0.4）。无论什么温度……
The scattering of focused beams of hexapole‐oriented t‐BuCl and CHF3 molecules from a graphite (0001) surface has been studied over the surface temperature range 165 < Ts<730 K. The detected number densities of the surface‐scattered beams are compared for parallel vs antiparallel incident orientation of the molecular dipole with respect to the surface normal. From the fractional difference in scattered signals, i.e., the so‐called steric effect, and from the scattering angular distributions of the unoriented molecules, the relative difference in scattering probabilities for opposite molecular orientations is obtained. For both molecules the magnitude of the relative difference in scattering (the steric effect) increases as Ts decreases. At the lowest surface temperature of 165 K the relative difference in scattering probability reaches +1.5 for t‐BuCl (and −0.8 for CHF3), approaching the largest possible magnitude of 2.0, as compared to +0.3 (and −0.4 for CHF3) at the highest temperatures. At all temperat...