探测液态水的自我电离与ab initio深潜力的分子动力学
Marcos Calegari Andrade1,2, Roberto Car1, Annabella Selloni1
1Chemistry Department, Princeton University, Princeton, NJ 08544.
概括
了解水的自我电离是酸化学的关键. 新的模拟显示,远程静电学和系统大小对于准确的结果至关重要,揭示了对水的洞察力.
科学领域:
- 物理化学 物理化学
- 计算化学的计算化学
- 材料科学 材料科学 材料科学
背景情况:
- 水的自我电离 (H2O H+ + OH−) 控制了水中的酸化学.
- 水自电离的微观机制很难通过实验和计算来研究.
- 准确的建模需要捕捉复杂的相互作用和系统动态.
研究的目的:
- 用先进的计算方法研究水自我电离的微观机制.
- 为了确定系统大小和静电相互作用对水自电离化的影响.
- 计算水离子对的自由能量概况和解离常数.
主要方法:
- 密度功能理论 (DFT) 与深度神经网络 (DNN) 潜力相结合.
- 改进的采样技术和全球酸集体变量.
- 水系统的原子模拟从64个H2O分子到500多个H2O分子.
主要成果:
- 在DNN潜力中明确纳入远程静电,对于准确的自由能量概况至关重要.
- 平均力对离子分离的潜力在 > 500 H2O 的系统中趋同.
- ~8 Å的分离距离被确定为超出离子分离工作可以忽略的门.
- 系统大小会影响水的重组和离子周围的局部秩序,从而影响趋同.
结论:
- 精确模拟水的自我电离需要大型系统大小和精确处理远程静电学.
- 热效应和静电相互作用在水自电离平衡中起着重要作用.
- 该研究提供了一个强大的计算框架,用于理解基本的水性化学过程.
更多相关视频
10:52Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics
Published on: April 12, 2019
12.8K
12:11Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
8.2K
相关概念视频
Intermolecular Forces
58.5K
Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen...
58.5K
Van der Waals Interactions
64.0K
Atoms and molecules interact with each other through intermolecular forces. These electrostatic forces arise from attractive or repulsive interactions between particles with permanent, partial, or temporary charges. The intermolecular forces between neutral atoms and molecules are ion–dipole, dipole–dipole, and dispersion forces, collectively known as van der Waals forces.
64.0K
Aqueous Solutions and Heats of Hydration
14.7K
Water and other polar molecules are attracted to ions. The electrostatic attraction between an ion and a molecule with a dipole is called an ion-dipole attraction. These attractions play an important role in the dissolution of ionic compounds in water.
When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution because water molecules surround and solvate the ions, reducing the strong electrostatic forces between them. This process...
When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution because water molecules surround and solvate the ions, reducing the strong electrostatic forces between them. This process...
14.7K
Solubility Equilibria: Ionic Product of Water
1.0K
Pure water is a weak electrolyte; only a small amount ionizes into hydrogen and hydroxide ions. At any given temperature, the concentration of undissociated water is almost constant, so the ionic product of water is the product of the hydrogen and hydroxide ion concentrations, denoted as Kw. The square root of Kw gives the individual ion concentrations.
The ionic product of water varies with temperature, and its value is 1.0 x 10−14 at standard experimental conditions. Per Le...
The ionic product of water varies with temperature, and its value is 1.0 x 10−14 at standard experimental conditions. Per Le...
1.0K
Intermolecular Forces in Solutions
33.8K
The formation of a solution is an example of a spontaneous process, a process that occurs under specified conditions without energy from some external source.
When the strengths of the intermolecular forces of attraction between solute and solvent species in a solution are no different than those present in the separated components, the solution is formed with no accompanying energy change. Such a solution is called an ideal solution. A mixture of ideal gases (or gases such as helium and argon,...
When the strengths of the intermolecular forces of attraction between solute and solvent species in a solution are no different than those present in the separated components, the solution is formed with no accompanying energy change. Such a solution is called an ideal solution. A mixture of ideal gases (or gases such as helium and argon,...
33.8K
Water: A Bronsted-Lowry Acid and Base
50.6K
The reaction between a Brønsted-Lowry acid and water is called acid ionization. For example, when hydrogen fluoride dissolves in water and ionizes, protons are transferred from hydrogen fluoride molecules to water molecules, yielding hydronium ions and fluoride ions:
50.6K
