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长期以来,由于实验测试和数据分析上的困难,对液态物质的性质和结构研究未能象研究晶态和非晶态固体物质那样有相应的发展。已发表的有关液态物质性质和结构的研究工作较少,至今对固—液相变的微观机理及液态金属和化合物的结构等许多问题仍不很清楚。液态是物质在自然界存在的主要形式之一,随着科学技术发展的需要,人们更为迫切地要求了解物质在液态时的结构和性质。研究液态物理中的问题愈来愈受到国内外的重视。液态物质的结构研究则是液态物理的一个关键问题。液态物质往往有很大的无序度,通常的结构测试手段难于得到有用的结构信息。由于X-ray absorption fine structure(XAFS)技术本身的特点,XAFS是研究无序体系结构很有效的方法,但目前研究液态物质取得的成果很少,主要有两方面的原因,一是要保持微米量级厚度的液态样品不漏光和不塌落较为困难;二是无序体系的XAFS数据分析需要选用适当的原子配位分布函数模型。本文用蒸发镀膜技术制备Ga样品,XAFS研究金属Ga从液氮温度一直到熔化为液态之后的结构变化。
For a long time, due to the difficulties in experimental testing and data analysis, the research on the properties and structures of liquid materials failed to develop as the research on crystalline and amorphous solid materials. The published research on the properties and structures of liquid substances is scarce. So far, many problems such as the microscopic mechanism of solid-liquid phase transitions and the structure of liquid metals and compounds have not been clarified. Liquid is one of the main forms in which matter exists in nature. With the development of science and technology, people are more urgently required to understand the structure and nature of matter when it is in liquid state. The research on the problem of liquid physics has been paid more and more attention both at home and abroad. The structural study of liquid materials is a key issue in liquid physics. Liquid materials often have a great degree of disorder, the usual structure of the test method is difficult to get useful structural information. Due to the characteristics of X-ray absorption fine structure (XAFS) technology, XAFS is a very effective method to study disordered architecture. However, the current research on liquid materials has achieved very few results. There are two main reasons for this. First, It is more difficult for the liquid sample of the order of magnitude to leak and not to collapse; secondly, the XAFS data analysis of the disorder system needs to select the appropriate atomic coordination distribution function model. In this paper, Ga samples were prepared by evaporation technique. The X-ray diffraction (XAFS) was used to study the structural changes of metal Ga from the liquid nitrogen temperature to the molten state.