原子からメソスケールの化学のための新しい計算手法を開発(Developing New Computational Methods for Atomic-to-Mesoscale Chemistry)

2024-06-04

2024-06-3 パシフィック・ノースウェスト国立研究所(PNNL)

多くの重要な化学反応は、複雑な溶液内での反応性や動力学を伴いますが、従来のシミュレーション技術では大規模な系や長時間のシミュレーションが困難です。研究者は、分子スケールと大規模スケールの両方をモデル化する新しいハイブリッド手法を開発しました。この手法は、溶媒系の観察結果を正確に再現しつつ、従来のシミュレーション手法に比べて計算効率を維持します。これにより、溶媒系や反応性のシミュレーションにおいて、精度と効率の両立が可能となり、さらに広範な溶媒反応の研究が進むことが期待されます。

＜関連情報＞

原子-メソスケール化学のためのAIMD/cDFTハイブリッドシミュレーションの開発と応用
Development and application of hybrid AIMD/cDFT simulations for atomic-to-mesoscale chemistr

Duo Song;Eric J. Bylaska;Maria L. Sushko;Kevin M. Rosso
The Journal of Chemical Physics Published:February 13 2024
DOI:https://doi.org/10.1063/5.0190686

Many important chemical processes involve reactivity and dynamics in complex solutions. Gaining a fundamental understanding of these reaction mechanisms is a challenging goal that requires advanced computational and experimental approaches. However, important techniques such as molecular simulation have limitations in terms of scales of time, length, and system complexity. Furthermore, among the currently available solvation models, there are very few designed to describe the interaction between the molecular scale and the mesoscale. To help address this challenge, here, we establish a novel hybrid approach that couples first-principles plane-wave density functional theory with classical density functional theory (cDFT). In this approach, a region of interest described by ab initio molecular dynamics (AIMD) interacts with the surrounding medium described using cDFT to arrive at a self-consistent ground state. cDFT is a robust but efficient mesoscopic approach to accurate thermodynamics of bulk electrolyte solutions over a wide concentration range (up to 2M concentrations). Benchmarking against commonly used continuum models of solvation, such as SMD, as well as experiments, demonstrates that our hybrid AIMD–cDFT method is able to produce reasonable solvation energies for a variety of molecules and ions. With this model, we also examined the solvent effects on a prototype S_N2 reaction of the nucleophilic attack of a chloride ion on methyl chloride in the solution. The resulting reaction pathway profile and the solution phase barrier agree well with experiment, showing that our AIMD/cDFT hybrid approach can provide insight into the specific role of the solvent on the reaction coordinate.