Unraveling the structure of high-pressure hydrous silicate melts by multi-dimensional NMR spectroscopy and ab intio calculations

通过多维核磁共振波谱和从头计算揭示高压水合硅酸盐熔体的结构

基本信息

批准号：
17340164
负责人：
XUE Xianyu
金额：
$ 8.19万
依托单位：
Okayama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17340164/
关键词：
melt glass structure water NMR aluminosilicate high pressure ab initio calculation 鉱物

项目摘要

The purpose of this study was to unravel the structure of hydrous (alumino)silicate melts (glasses) at high pressure in order to understand the behavior of natural magmas. The main achievements are outlined below:1.Development of multi-nuclear, multi-dimensional NMR techniques. Multi-dimensional NMR techniques are particularly powerful structural tools because of the direct information they provide about atomic connectivities. We have succeeded in a variety of NMR measurements including ^1H DQ (double quantum) MAS NMR, ^<27>Al 3Q (triple quantum) MAS NMR, and ^<27>Al-^1H HETCOR (heteronuclear correlation) and 3QMAS/HETCOR NMR.2.Settling a long-term controversy concerning the water dissolution mechanism in polymerized aluminosilicate melts. By using above techniques, we have confirmed that the dissolution of water in polymerized aluminosilicate melts results in the depolymerization of the network structure through formation of SiOH/AlOH.3.Unraveling the compositional dependency of water … More dissolution mechanisms in aluminosilicate melts. Our systematic study over a range of compositions, coupled with ab intio calculations, has revealed that the dissolution of water in (alumino)silicate melts/glasses involves two competing processes : (1) formation of SiOH/AlOH and depolymerization of the network structure, and (2) formation of free OH and polymerization of the network structure, with the latter favored by depolymerized compositions with cations of large field strength. Four-, five-and six-coordinate Al were found to coexist in hydrous Ca-and Mg-aluminosilicate glasses.4.NMR study of high-pressure hydrous minerals. A similar study was also carried out on high-pressure hydrous minerals. This is not only important for understanding the structures of mantle minerals themselves, but also provided insights into the high-pressure behavior of hydrous melts/glasses.5.Development of synthesis method for ^<17>O-enriched oxides. We have succeeded in synthesizing ^<17>O-enriched oxides with high yield. This is essential for ^<17>O NMR measurements on high-pressure materials of limited quantity. Less

这项研究的目的是阐明高压下液压（铝粉）硅酸盐熔体（玻璃）的结构，以了解天然岩浆的行为。主要成就如下：1。多核，多维NMR技术的开发。多维NMR技术是特别强大的结构工具，因为它们提供了有关原子连接性的直接信息。我们已经成功地进行了多种NMR测量，包括 ^1H DQ（双量子）MAS NMR， ^<27> Al 3Q（三量子）MAS NMR和 ^<27> al- ^1H hetcor（杂核相关）和3QMas/HetCor nmr.2.St nmr.2.St nmr.2。融化。通过使用上述技术，我们已经证实，聚合铝蛋白融化中水的溶解导致网络结构通过SIOH/aloH的形成而导致网络结构的解聚。3。unravel水的组成依赖性…铝糖量化融合中的溶解机制更加溶解。我们对一系列组合物的系统研究，再加上AB Intio的计算，表明（铝制）硅酸盐熔体/玻璃中的水溶解涉及两个竞争过程：（1）SIOH/ALOH的形成以及网络结构的沉积以及（2）（2）自由且与网络结构的自由形成，并通过层构成层构成，并构成了层构成的构成。发现四个，五和六坐标的Al可以在含水Ca和Mg-铝硅酸盐玻璃中共存。4.NMR研究高压液压矿物质。还对高压液压矿物进行了类似的研究。这不仅对于理解地幔矿物本身的结构很重要，而且还提供了对含水熔体/玻璃的高压行为的见解。5。 ^<17> o-富集氧化物的合成方法的开发。我们成功地合成了 ^<17> o-富集的氧化物，产量很高。这对于有限数量的高压材料上的 ^<17> o NMR测量至关重要。较少的