X光反射曲线峰强度的理论计算1概述-复旦大学物理教学试验中心.PDF

X 光反射曲线峰强度的理论计算 李 达 （复旦大学材料科学系，上海，200433） 摘要：使用X 射线实验仪，通过对LiF （晶面距d=2.01Å）晶体的耦合θ -2θ 扫描，得到计数率 R和散射角 θ 之间的关系图谱，即为X光反射曲线。先后采用菲涅耳公式、光栅方程对反射强度进行理论计算， 但与实验结果的符合程度都不好。中南大学材料科学与工程学院的课件上介绍了电子、原子、晶胞 等对 X光的散射机制，结合其他参考文献最终获知了X光光强关于散射角θ 和晶体结构因子FHKL 等 2 2 一些参数间的关系。推导表明，光强I 正比于(1+cos2θ )/(sin θ cosθ ),也正比于晶体结构因子的 平方 2 | FHKL | 。 关键词：X光 强度 理论计算 散射角 晶体结构因子 Theoretical calculation of peak intensity on X-ray reflection curve LI Da (Dept. of Material Science, Fudan University, Shanghai, 200433) Abstract: A diagram of relations between counting rate R and scattering angle θ was obtained via X-ray apparatus coupled θ ~2 θ scanning on LiF crystal with spacing d=2.01 Å. This diagram is also called X-ray reflection curve. Fresnel’s equation and grating formula were used to launch theoretical calculation on reflection intensity, but the result did not well-fit experimental consequence. Courseware from MSE introduced scattering mechanism of electrons, atoms and cells. With the help of some other references, a formula revealing relations between X-ray intensity and parameters such as scattering angle θ and structure factor Fhkl was finally acquired. Deduction showed that X-ray intensity was 2 2 2 proportional to (1+cos 2θ )/(sin θ cosθ ), as well as the square of structure factor, |Fhkl | . Keywords: X-ray; Intensity; Theoretical calculation; Scattering angle; Structure factor 11 概 概 述述 11 概概 述述 自1912年小