Molecular models of hydroxide, oxyhydroxide, and clay phases and the development of a general force field
Molecular models of hydroxide, oxyhydroxide, and clay phases and the development of a general force field
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DOI：
10.1021/jp0363287
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发表时间：
2004-01-29
影响因子：
3.3
通讯作者：
Kalinichev, AG
中科院分区：
文献类型：
--
作者：
Cygan, RT;Liang, JJ;Kalinichev, AG
化学和放射性废物在环境中的命运与自然相通过化学吸附和沉淀过程减弱和固定污染物的能力有关。我们在原子水平上对这些复杂过程的理解是通过一些实验和分析方法提供的，例如x射线吸收和核磁共振光谱。然而，由于粘土和其他水合矿物的结构和组成的复杂性，以及实验方法固有的不确定性，应用理论分子模型对这些现象进行基本的原子水平的理解、解释和预测是很重要的。在这项工作中，我们开发了一个通用力场CLAYFF，适用于模拟水合和多组分矿物系统及其与水溶液的界面。原子间电位是由各种简单水合化合物的结构和光谱数据的参数化得到的。一个灵活的基于spc的水模型被用来描述水和羟基的行为。通过对DFT结果的Mulliken和ESP分析，用Lennard-Jones函数和带部分电荷的库仑项描述了金属-氧相互作用。评估了体结构、松弛表面结构和插层过程，并将其与实验和光谱结果进行了比较，以进行验证。我们的方法与大多数其他方法不同，因为我们将大多数原子间的相互作用视为非键。这使我们能够有效地将力场用于各种各样的相，并适当地考虑流体相和固体之间的能量和动量传递，同时保持参数的数量足够小，以便对相对较大和高度无序的系统进行建模。粘土、氢氧化物和氢氧化物相及其与水溶液界面的模拟结合了能量最小化和分子动力学方法来描述这些系统中水、羟基、表面物质和插层物的结构和行为。迄今为止获得的结果表明，CLAYFF具有良好的发展前景，可以发展成为一个广泛适用和广泛有效的力场，用于与粘土和其他粘土相关相的流体界面的分子模拟，以及其他具有复杂、无序和经常不确定结构和组成的无机材料。
The fate of chemical and radioactive wastes in the environment is related to the ability of natural phases to attenuate and immobilize contaminants through chemical sorption and precipitation processes. Our understanding of these complex processes at the atomic level is provided by a few experimental and analytical methods such as X-ray absorption and NMR spectroscopies. However, due to complexities in the structure and composition of clay and other hydrated minerals, and the inherent uncertainties of the experimental methods, it is important to apply theoretical molecular models for a fundamental atomic-level understanding, interpretation, and prediction of these phenomena. In this effort, we have developed a general force field, CLAYFF, suitable for the simulation of hydrated and multicomponent mineral systems and their interfaces with aqueous solutions. Interatomic potentials were derived from parametrizations incorporating structural and spectroscopic data for a variety of simple hydrated compounds. A flexible SPC-based water model is used to describe the water and hydroxyl behavior. Metal-oxygen interactions are described by a Lennard-Jones function and a Coulombic term with partial charges derived by Mulliken and ESP analysis of DFT results. Bulk structures, relaxed surface structures, and intercalation processes are evaluated and compared to experimental and spectroscopic findings for validation. Our approach differs from most others in that we treat most interatomic interactions as nonbonded. This allows us to effectively use the force field for a wide variety of phases and to properly account for energy and momentum transfer between the fluid phase and the solid, while keeping the number of parameters small enough to allow modeling of relatively large and highly disordered systems. Simulations of clay, hydroxide, and oxyhydroxide phases and their interfaces with aqueous solutions combine energy minimization and molecular dynamics methods to describe the structure and behavior of water, hydroxyl, surface species, and intercalates in these systems. The results obtained to date demonstrate that CLAYFF shows good promise to evolve into a widely adaptable and broadly effective force field for molecular simulations of fluid interfaces with clays and other clay-related phases, as well as other inorganic materials characterized by complex, disordered, and often ill-determined structure and composition.