通过DFT模拟的水合电子的部分摩尔溶解体积
William R Borrelli1, Kenneth J Mei1, Sanghyun J Park1
1Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States.
密度函数理论 (DFT) 对水合电子的模拟显示,与实验相比,即使在大型系统大小中,其部分摩尔体积也被严重低估. 这表明模拟的水化结构中的不准确性.
科学领域:
- 计算化学的计算化学
- 物理化学 物理化学
- 量子化学 是一个量子化学.
背景情况:
- 准确模拟水合电子对于理解其化学性质至关重要.
- 将模拟模型与实验数据进行比较是具有挑战性的,因为不同的溶解结构.
- 柯克伍德-巴夫理论提供了一种方法,将模拟的水化结构与实验可测量的特性 (如部分体积) 联系起来.
研究的目的:
- 使用ab-initio密度函数理论 (DFT) 模拟来计算水合电子的部分摩尔体积.
- 根据实验数据,评估基于DFT的水合电子模型的收性和准确性.
- 为了确定模拟和实验溶解结构之间的差异.
主要方法:
- 使用密度函数理论 (DFT) 与混合函数 (PBEh-D3) 的ab-initio分子动力学模拟.
- 使用柯克伍德-巴夫理论从水化电子-水辐射分布函数计算部分摩尔体积.
- 模拟盒大小的系统变化 (最多128个水分子).
主要成果:
- 在DFT模拟中,水合电子的部分摩尔体积即使在128个水分子中也不会趋同.
- DFT模拟低估了实验部分体积的最大尺寸的约2倍,在常见的64水尺寸的约3.5倍.
- 对更大的系统大小的推断表明,DFT模型可以匹配实验值,但目前的模拟在计算上是难以处理的.
结论:
- 目前使用PBEh-D3函数的基于DFT的模拟无法准确地捕捉水合电子的溶解结构.
- 趋同需要显著的系统大小,这给计算带来了挑战.
- 需要进一步调查,以了解模拟的电子-水辐射分布函数中的偏差.
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