Investigation of dynamical processes at liquid surfaces by molecular scattering
Investigation of dynamical processes at liquid surfaces by molecular scattering
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通过分子散射研究液体表面的动力学过程
DOI：
10.1039/ft9938903877
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
M. Zidan
中科院分区：
文献类型：
--
作者：
A. Kenyon;A. J. McCaffery;C. Quintella;M. Zidan
我们报道了液体表面激光-分子束散射的研究结果。以I2为探针分子，测定了I2从液体样品表面散射前后的内部量子态分布。激光诱导荧光信号的时间分辨率使我们能够区分直接非弹性散射和捕获随后解吸的过程。随着激光定时的改变以及液体样品的改变，可以观察到光谱图案的显著差异。表面化学性质的影响在可能具有反应通道的镓中特别明显。基于分子在液体表面的受体模式和促进模式的可用性，分析了表面相关的捕获和脱附过程。与CH3基团相关的模式似乎在吸收气相小分子的平动能量方面特别有效，而CF3基团的那些模式则不那么有效。聚二甲基硅氧烷具有多种受体模式，是一种有效的捕集物种。此外，它还具有有效的启动子模式，Si-O-Si键的扭转运动可能与这一作用密切相关。
We report the results of a laser–molecular beam scattering study of liquid surfaces. I2 is used as a probe molecule and its internal quantum-state distribution is determined both before and after scattering from the surface of liquid samples. Time resolution of the laser-induced fluorescence signal allows us to distinguish the processes of direct inelastic scatter and trapping followed by desorption. Marked differences in the spectral patterns, are observed as laser timing is varied and also when the liquid sample is changed. The effect of the chemical nature of the surface is particularly marked in gallium for which reactive channels are likely. An analysis of surface-dependent trapping and desorption is presented based on the availability of acceptor and promoter modes of molecules in the liquid surface. Modes associated with the CH3 group appear to be particulary efficient in absorbing the translational energy of small gas-phase molecules whilst those of the CF3 group are less effective. Polydimethylsiloxane has a range of acceptor modes and hence is an efficient trap species. Furthermore it possesses effective promoter modes and torsional motions of the Si—O—Si link may be closely involved in this role.