在这项研究中，构建了反应力场 (ReaxFF) 和电子力场 (eFF) 分子动力学 (MD) 模拟的组合，以揭示电场在原子和亚原子尺度上对乙醇氧化反应的影响的基本机制。总共进行了 21 次 ReaxFF MD 模拟和 35 次 eFF MD 模拟。ReaxFF MD 结果表明，乙醇氧化反应是一个两阶段过程，其中电场在每个阶段发挥不同的作用。第一阶段的特点是乙醇分子的分解，其中电场通过改变含碳分子/自由基的动能大约为 100-1000 kJ/mol 并改变分子构象，从而影响分解反应速率。键解离能。在氧分子参与反应的第二阶段，电场通过改变反应路径来影响反应。eFF MD 模拟的应用首次将我们对电场对乙醇氧化反应的影响的理解扩展到亚原子尺度。结果表明，电场对电子能量的影响约为 10-100 kJ/mol。本研究还解释了先前关于电场对反应途径和荧光实验观察的影响的发现，并为“离子风”和化学驱动的假设提供了支持。这项研究为电场辅助的反应提供了前所未有的洞察力，这可能有助于设计现实的场辅助燃烧系统。
In this research, a combination of reactive force field (ReaxFF) and electron force field (eFF) molecular dynamics (MD) simulations is constructed to reveal the fundamental mechanisms for the influence of the electric field on ethanol oxidation reactions at atomic and subatomic scales. In total, 21 ReaxFF MD simulations and 35 eFF MD simulations have been conducted. ReaxFF MD results indicate that the ethanol oxidation reaction is a two-stage process where the electric field plays varied roles in each stage. The first stage features the decomposition of ethanol molecules, in which the electric field influences the decomposition reaction rate by changing the kinetic energy of carbon-containing molecules/radicals on the order of 100–1000 kJ/mol and altering the molecular conformation and thereby the bond dissociation energy. At the second stage where oxygen molecules participate in the reaction, the electric field affects reactions by modifying the reaction pathways. The application of the eFF MD simulations, for the first time, extends our understanding of the electric field effects on ethanol oxidation reaction to subatomic scales. The results indicate that the electric field modifies the electron energy on the order of 10–100 kJ/mol. The present study also offers interpretation of previous findings on electric field effects on reaction pathways and fluorescence experimental observations, and provides support for both “ionic wind” and chemistry-driven hypotheses. This research provides unprecedented insight into reactions aided by the electric field, which potentially can facilitate the design of realistic field-assisted combustion systems.
