气相电子衍射和SF6分子中电荷的再分布

近年来，由于高能电子散射技术的发展，自由小分子中电荷密度的分布成了散射工作者注意的一个热点，已有专著论及［1］．关于自由小分子中电荷的分布，迄今为止，理论方面的信息来源主要是量子化学计算；而实验测定方面，高能量电子散射是一种重要的方法．原子形成分子时电荷密度的改变，主要是在价壳层，和中性原子的电荷分布相比较，这种改变是较小的，因此对实验工作者的要求就很高．目前已发表的研究工作，大都为很小的分子（如双原子分子），从理论和实验两方面去求得进展．理论上作散射截面计算，然后与分子散射强度曲线作比较，如Sz…

Gas Electron Diffraction and Charge Redistribution in SF_6 Molecule

Independent atom model (IAM) is generaly used in gaseous electron diffraction (GED) experiment. This means that the effect of the charge redistribution in a molecule is neglected in general case in GED data analysis and the information of the effect could be taken from the residual intensity.In this work, various methods were suggested to calculate the elastic scattering factors for S, F atoms in SF6 molecule (modified IAM or MIAM) and the residual intensity of 40keV electrons scattered by the same molecule. Bonham-type parameter method was selected to acheive good agreement with experimental results and the charge redistribution was determined according to these parameters. Further comparison was made between different methods and their results.