非晶态物质径向分布函数测定的最大熵方法

本文导出一种计算非晶态物质径向分布函数的最大熵方法,给出非晶态D₂O径向分布函数的计算实例,并与传统的傅里叶变换法进行了比较,结果表明,最大熵方法对结构信息的反映更为敏感,因而,在同样实验数据的条件下,最大熵方法可能比传统的傅里叶变换法提供更多的结构信息。 关键词：

MAXIMUM ENTROPY METHOD IN STRUCTURAL ANALYSIS

Information theory provides a constructive criterion for setting up probability distributions on the basis of partial knowledge, and leads to a type of statistical inference which is called the maximumentropy estimate. It is the least biased estimate possible on the given information, i.e., it is maximally noncommittal with regard to missing information.The principle of maximum entropy, which has proven useful in other contexts, is adopted here to design a procedure for obtaining structural information from an incomplete set of diffraction data. A comparison is made between the proposed procedure and the conventional Fourier inversion method used in RDF analysis of non-crystalline materials. The maximum-entropy method is found to have a higher resolution and also the advantage of no adjustable parameters with a high degree of reliability.This method is iterative and uses more computer time than direct techniques; however, a number of comparative examples indicate that a significant improvement on the resultant structure in quality and resolution is possible with only a few iterations.