Zhou Rui, Bao Luyao, Bu Weifeng, Zhou Feng
Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry, and College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China.
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
J Chem Phys. 2024 Aug 7;161(5). doi: 10.1063/5.0222514.
ReaxFF reactive molecular dynamics has significantly advanced the exploration of chemical reaction mechanisms in complex systems. However, it faces several challenges: (1) the prevalent use of excessively high temperatures (>2000 K), (2) a time scale considerably shorter than the experimental timeframes (nanoseconds vs seconds), and (3) the constraining impact of dimensionality growth due to collective variables on the expansiveness of research systems. To overcome these issues, we introduced Parallel Collective Variable-Driven Adaptive Accelerated Reaction Molecular Dynamics (PCVR), which integrates metadynamics with ReaxFF. This method incorporates bond distortion based on each bond type for customized Collective Variable (CV) parameterization, facilitating independent parallel acceleration. Simultaneously, the sampling was confined to fixed cutoff ranges for distinct bond distortions, effectively overcoming the challenge of the CV dimensionality explosion. This extension enhances the applicability of ReaxFF to non-strongly coupled systems with numerous reaction energy barriers and mitigates the system size limitations. Using accelerated reactive molecular dynamics, the oxidation of ester-based oil was simulated with 31 808 atoms at 500 K for 64 s. This achieved 61% efficiency compared to the original ReaxFF and was ∼37 times faster than previous methods. Unlike ReaxFF's high-temperature constraints, PCVR accurately reveals the pivotal role of oxygen in ester oxidation at industrial temperatures, producing polymers consistent with the sludge formation observed in ester degradation experiments. This method promises to advance reactive molecular dynamics by enabling simulations at lower temperatures, extending to second-level timescales, and accommodating systems with millions of atoms.
ReaxFF反应分子动力学在复杂系统化学反应机理的探索方面取得了显著进展。然而，它面临着几个挑战：（1）普遍使用过高的温度（>2000 K）；（2）时间尺度比实验时间框架短得多（纳秒与秒）；（3）由于集体变量导致的维度增长对研究系统扩展性的限制影响。为了克服这些问题，我们引入了并行集体变量驱动的自适应加速反应分子动力学（PCVR），它将元动力学与ReaxFF相结合。该方法基于每种键型合并键畸变，用于定制集体变量（CV）参数化，便于独立的并行加速。同时，采样被限制在不同键畸变的固定截止范围内，有效克服了CV维度爆炸的挑战。这种扩展增强了ReaxFF对具有众多反应能垒的非强耦合系统的适用性，并减轻了系统尺寸限制。使用加速反应分子动力学，在500 K下对含31 808个原子的酯基油氧化进行了64秒的模拟。与原始ReaxFF相比，效率提高了61%，比以前的方法快约37倍。与ReaxFF的高温限制不同，PCVR准确揭示了氧气在工业温度下酯氧化中的关键作用，生成的聚合物与酯降解实验中观察到的污泥形成一致。该方法有望通过实现低温模拟、扩展到二级时间尺度以及容纳数百万原子的系统来推动反应分子动力学的发展。
