A Study of the Incorporation of Water in Earth Materials Based on Electron Density Distributions

基于电子密度分布的地球材料中水的掺入研究

• 批准号: 0229472
• 负责人: Nancy Ross
• 金额: $ 20.9万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-01 至 2006-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0229472&HistoricalAwards=false
• 关键词: Study; Incorporation; Water; Earth; Materials

RossEAR-0229472Research will be undertaken to advance the geochemist's - mineralogist's understanding of the mechanisms controlling the incorporation of water in earth materials and properties of the bonded interactions, both in minerals and representative molecules. Sites that are susceptible to electrophilic attack will be located, at the atomic level, within the crystal structures and on the surfaces of minerals. These calculations will identify potential sites for incorporation of hydrogen in nominally anhydrous minerals, both as hydroxyl groups and as water molecules. In addition, the adsorption and alignment of molecules like water, the hydronium and hydroxyl ions within the structures will be determined. These goals will be accomplished by evaluating the bond critical point properties of the calculated electron density distributions for a wide variety of minerals. The properties of the electron density will be determined and the local maxima in the Laplacian distributions for the valence shell electrons of the bonded atoms will be located. Electron density distributions will also be studied at pressure to monitor how these sites behave when compressed.A knowledge of the location and structure of the internal and surface sites that are susceptible to electrophilic attack will advance our understanding, at the atomic level, of the incorporation of hydrogen in minerals as well as the chemical reactivities of silicates and oxides. It is further anticipated that this work will not only provide a theoretical basis for the modeling of internal and surface reactions of earth materials, but that it will lead, in future studies, to a better understanding of the atomistic properties and pathways involved in weathering, bacterial attack, chemisorption and other important geochemical processes.

研究将促进地球化学家和矿物学家对控制水在地球材料中的结合的机制和矿物和代表性分子中键合相互作用的性质的理解。易受亲电性攻击的地点将位于原子水平上，在晶体结构内和矿物表面上。这些计算将确定氢在名义上无水矿物中作为羟基和水分子结合的潜在位置。此外，分子的吸附和排列，如水，水合氢离子和羟基离子的结构将被确定。这些目标将通过评估各种矿物计算的电子密度分布的键临界点特性来实现。确定电子密度的性质，并确定键合原子的价壳层电子在拉普拉斯分布中的局部最大值。电子密度分布也将在压力下进行研究，以监测这些位置在压缩时的行为。了解易受亲电攻击的内部和表面位点的位置和结构，将提高我们在原子水平上对矿物中氢的掺入以及硅酸盐和氧化物的化学反应性的理解。进一步预计，这项工作不仅将为地球材料内部和表面反应的建模提供理论基础，而且将在未来的研究中更好地了解风化、细菌攻击、化学吸附和其他重要地球化学过程的原子性质和途径。