由于X射线吸收精细结构（X—rayabsorption fine structure，XAFS）可以原位探测吸收原子的2～3个邻近配位壳层，获得目标元素的电子结构信息和化学结构信息，所以XAFS已成为微观领域最重要的结构分析工具，丰富了我们对元素的重要化学...由于X射线吸收精细结构（X—rayabsorption fine structure，XAFS）可以原位探测吸收原子的2～3个邻近配位壳层，获得目标元素的电子结构信息和化学结构信息，所以XAFS已成为微观领域最重要的结构分析工具，丰富了我们对元素的重要化学性质和反应过程的认识。本文简述了XAFS的基本原理，探讨了样品制备、测试及数据分析等过程需关注的问题，重点综述了应用XAFS研究土壤重金属和营养元素的形态、土壤固一液界面的反应过程和机理，并指出其应用的局限性和未来发展的前景，旨在推动我国XAFS在土壤科学中的应用。由于土壤中界面反应的复杂性，XAFS应结合其他结构分析技术，结构分析技术应结合宏观数据和计算机模拟，土壤学应与其他学科交叉、融合，只有这样，才有可能在时间和空间尺度上阐明土壤组分在环境界面上的复杂反应过程和机理。展开更多
The coordination of Mg in spinel, diopside and pyrope is 4,6 and 8,respectively. The spectral profiles of these minerals are different, and the Mg K edge shifts towards higher energy with increase in the coordination ...The coordination of Mg in spinel, diopside and pyrope is 4,6 and 8,respectively. The spectral profiles of these minerals are different, and the Mg K edge shifts towards higher energy with increase in the coordination number of Mg. The former may be related to the coordination geometry, and the latter to the Mg—O band distance. Mg K edge(peak 1) tends to shift to higher energy with the increase in Mg-O band distance, but also to shift to lower energy with increase in the band valence of Mg with oxygen. Mg in CaMgSi 2O 6(Di) NaAlSi 3O 8(Ab)glasses may be multiple structural sites.展开更多
文摘由于X射线吸收精细结构（X—rayabsorption fine structure，XAFS）可以原位探测吸收原子的2～3个邻近配位壳层，获得目标元素的电子结构信息和化学结构信息，所以XAFS已成为微观领域最重要的结构分析工具，丰富了我们对元素的重要化学性质和反应过程的认识。本文简述了XAFS的基本原理，探讨了样品制备、测试及数据分析等过程需关注的问题，重点综述了应用XAFS研究土壤重金属和营养元素的形态、土壤固一液界面的反应过程和机理，并指出其应用的局限性和未来发展的前景，旨在推动我国XAFS在土壤科学中的应用。由于土壤中界面反应的复杂性，XAFS应结合其他结构分析技术，结构分析技术应结合宏观数据和计算机模拟，土壤学应与其他学科交叉、融合，只有这样，才有可能在时间和空间尺度上阐明土壤组分在环境界面上的复杂反应过程和机理。
文摘The coordination of Mg in spinel, diopside and pyrope is 4,6 and 8,respectively. The spectral profiles of these minerals are different, and the Mg K edge shifts towards higher energy with increase in the coordination number of Mg. The former may be related to the coordination geometry, and the latter to the Mg—O band distance. Mg K edge(peak 1) tends to shift to higher energy with the increase in Mg-O band distance, but also to shift to lower energy with increase in the band valence of Mg with oxygen. Mg in CaMgSi 2O 6(Di) NaAlSi 3O 8(Ab)glasses may be multiple structural sites.
