Size effects in the structure and dynamics of CO2 clusters
Size effects in the structure and dynamics of CO2 clusters
复制标题
CO2 团簇结构和动力学的尺寸效应
DOI：
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发表时间：
1984
期刊：
影响因子：
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通讯作者：
B. Raoult
中科院分区：
文献类型：
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作者：
G. Torchet;H. Bouchier;J. Farges;M. F. Feraudy;B. Raoult
团簇是在自由射流膨胀中形成的，并通过电子衍射进行了研究，每个团簇在102-105个CO2分子之间。当团簇包含超过103个分子时，晶体学方法提供平均结构和动力学参数，而对于较小的团簇，则使用简单均匀模型的衍射模式和计算的衍射函数之间的比较。研究发现，即使二氧化碳簇的分子数少于102个，也会呈现出体积立方结构。当平均簇大小减少到103个分子时，我们观察到晶格参数线性减少，均方根原子位移增加，由于分子的振动运动，这种增加对于O原子比C原子更大。计算出的衍射函数可以定量地研究最近邻分子的相关运动，并且与实验曲线在102 ~ 103分子/克/克范围内的结果吻合得很好。
Clusters are formed in a free jet expansion and studied by electron diffraction, in the range 102–105 CO2 molecules per cluster. When clusters contain more than about 103 molecules, crystallographic methods provide mean structural and dynamical parameters while a comparison between diffraction patterns and calculated diffraction functions of a simple homogeneous model is used in the case of smaller clusters. CO2 clusters are found to present the bulk cubic structure even when they contain less than some 102 molecules. When decreasing the mean cluster size down to some 103 molecules, we observe a linear decrease in the lattice parameter and an increase in the rms atomic displacements, this increase being larger for O atoms than for C atoms due to the molecular librational motions. The calculated diffraction functions make it possible to study quantitatively the correlated motions of nearest neighbor molecules and are in very good agreement with the experimental curves in the range 102–103 molecules per clu...