X射线小角散射中的粒子间相互干涉效应

X射线小角散射中的粒子间干涉效应是影响实验结果的一个重要因素.已有的若干粒子间干涉的模型和理论不能很好地解释实验事实.实际使用的粒子间干涉效应校正方法为不同浓度试样归一化散射曲线作图外推法.然而在材料科学的许多应用中常常无法测量不同浓度的稀释试样.因此找出干涉函数的经验方程有重要意义.该文测定了超细二硫化钼不同浓度试样在不同角度下的强度衰减因子,从而导出了干涉函数的经验方程:(?)~(-1)=1+2.5ω~(1.4)+2θ°(15.4ω~(0.5)-23.6ω~2-1.3ω~(0.01))]~(-1)

EFFECTS OF INTERP ARTICLE INTERFERENCE IN SMALL-ANGLE X-RAY SCATTERING

According to the small-angle X-ray scattering theory, it is always assumed that the scattering intensities of particles are simply added up to give the total diffraction pattern. This is true only for a very dilute particle system. However, with increasing concentration, some effects of interpartiole interference should be expected. Several models and theories of interpartiole interference have been presented but no rigorous solution can be given so far. In the practical case, the magnitude of the concentration effects can be seen by plotting the scattering curves of the various concentrated particle systems, normalized to unit concentration. Sometimes it is impossible to measure a series of concentrations in the applications of materials science, such as determining the size distribution of a mioro-inhomogeneous region, global droplets of spinodal decomposition, precipitation of the second phase, condensation of vacancies and defects in bulk materials. 'Therefore, it is of importance to find an empii-ical equation of the interference function. The intensities of ultrafine MoSs samples in several concentrations at different angles are determined in detail. The empirical equation of the interference Junction is deduced as: