Yang Walt, Lee Chin, Saric Steven, Pohl Marvin N, Neumark Daniel M
Department of Chemistry, University of California, Berkeley, California 94720, USA.
Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
J Chem Phys. 2023 Aug 7;159(5). doi: 10.1063/5.0159796.
The evaporation and scattering of Ne, CD4, and D2O from a dodecane flat liquid jet are investigated in a molecular beam apparatus. The experiment yields translational energy distributions as a function of scattering angle by means of a rotatable mass spectrometer. In the evaporation experiments, one observes a Maxwell-Boltzmann distribution with a cos θ angular distribution superimposed on a weak, isotropic background. The scattering experiments show contributions from impulsive scattering and thermal desorption. At select incident angles for the three systems, angular distributions show super-specular scattering for the impulsive scattering channel, an effect attributed to anisotropic momentum transfer to the liquid surface. The impulsive scattering channel is analyzed with a soft-sphere model to explore energy transfer between the scatterer and liquid as a function of deflection angle. Compared to Ne scattering, the polyatomic gases exhibit more thermal desorption and, in the impulsive scattering channel, a higher degree of internal excitation.
在分子束装置中研究了氖（Ne）、氘代甲烷（CD4）和重水（D2O）从十二烷平面液体射流中的蒸发和散射。通过可旋转质谱仪，该实验得出了作为散射角函数的平动能量分布。在蒸发实验中，人们观察到麦克斯韦-玻尔兹曼分布，在微弱的各向同性背景上叠加了一个cosθ角分布。散射实验显示了脉冲散射和热脱附的贡献。对于这三个系统在选定的入射角下，角分布显示脉冲散射通道存在超镜面散射，这种效应归因于向液体表面的各向异性动量转移。用软球模型分析脉冲散射通道，以探索散射体与液体之间的能量转移作为偏转角的函数。与Ne散射相比，多原子气体表现出更多的热脱附，并且在脉冲散射通道中具有更高程度的内激发。
