一种简化的理论计算RIR值的方法

A Simplified Method for Theoretically Calculating RIR Values

摘要: 参考强度比(RIR)法是一种高效、简单的XRD定量相分析(QPA)方法，其精度主要取决于RIR值的准确度，然而，当前主流的理论计算RIR方法只能计算出已知晶体结构物相的RIR值。对此，一个基于晶胞总的相干散射能力的计算方法被提出，该方法可以用于计算未知晶体结构物相的RIR值，但计算门槛较高，所需参数较多。因此，为了进一步提高理论计算RIR值的适用范围，本文在相干散射计算法的基础上，进一步指出只需要知道晶体的晶胞参数、物相的化学式以及相对应的衍射信息就可以计算出RIR值。经过与开源晶体学数据库COD提供的RIR参数对比，发现该方法计算出来的RIR值与主流的理论计算法得到的RIR值具有较好的一致性，且该方法无需知道晶体结构的信息和晶胞的化学含量。因此，该方法具有广泛的适用性和巨大的应用潜力，进一步提高了计算法的适用范围，有利于促进RIR法在QPA中的应用。

Abstract: The Reference Intensity Ratio (RIR) method is an efficient and simple approach for Quantitative Phase Analysis (QPA) in X-Ray Diffraction (XRD). Its accuracy mainly depends on the reliability of the RIR values. However, current mainstream theoretical methods can only calculate RIR values for phases with known crystal structures. To address this issue, a method based on the total coherent scattering power of the unit cell has been proposed. This method can be used to calculate RIR values for phases with unknown crystal structures, but it has a high computational threshold and requires many parameters. Therefore, to further improve the applicability of theoretical RIR calculations, this work develops the coherent scattering approach further. It shows that the RIR value can be calculated using only the unit cell parameters, the chemical formula of the phase, and the corresponding diffraction information. By comparing the calculated results with the RIR data provided by the Crystallography Open Database (COD), good agreement is observed between this method and mainstream theoretical methods. In addition, this method does not require detailed crystal structure information or the chemical content of the unit cell. Therefore, it has wide applicability and strong potential for practical use. It also expands the scope of theoretical RIR calculations and helps promote the application of the RIR method in QPA.