氧原子和烃类分子反应的动力学研究

The oxygen atom is a universal radical in the combustion, and its reactions with hydrocarbon molecules are important elementary reactions in the combustion of hydrocarbon fuel. Important information for the combustion kinetics of complex hydrocarbon fuel can be provided by investigating the dynamical mechanism of these elementary reactions. Here, a most reliable dynamical study will be carried out for the reactions of O(1D) with CH4, C2H6 and C3H8, and the reactions of O(3P) with C2H4 and C3H6 in this project. Based on high-level ab initio energy points, accurate, global, full-dimensional potential energy surfaces (PESs) will be constructed by permutationally invariant polynomial fitting method, and the minimum energy crossings and spin-orbit couplings will be investigated and calculated. The detailed dynamical mechanism and non-adiabatic dynamical effects will be investigated by comprehensive quasiclassical trajectory and trajectory surface-hopping calculations. The branching ratios of various products channels, rate constants, product translational energy and internal energy distributions, differential cross sections and collisional energy transfer will be calculated at varying collision energies and temperatures will be calculated. The correlations among those dynamical and kinetic features for different hydrocarbon reactants will be deeply investigated. These calculations and investigations will provide theoretical foundations for studying the temperature and pressure dependent processes in elementary reactions of hydrocarbon fuel combustion.

氧原子是燃烧过程中普遍存在的自由基，它和烃类分子反应是碳氢燃料燃烧中重要的基元反应，研究这些基元反应的动力学机理将对复杂碳氢燃料的燃烧动力学研究提供重要的信息。本项目拟对O(1D)+CH4/ C2H6/C3H8以及O(3P)+ C2H4 /C3H6反应开展最为可靠的动力学研究。基于高精度的从头算能量点，用交换不变多项式拟合方法构建精确的全维全域势能面，探讨势能面交叉点和旋轨耦合。用准经典轨线和势能面跳跃方法研究氧原子和烃类分子反应的微观机理和非绝热动力学效应，在不同碰撞能和温度下计算各产物通道的分支比、速率常数、产物平动能和内能分布以及微分散射截面，碰撞能量转移，并深入探讨不同烃类反应物间的动力学关联，为研究温度、压力相关的碳氢燃料燃烧基元反应过程提供理论依据。

在项目执行期间，我们按研究计划对燃烧中重要化学反应开展了可靠的动力学研究，并取得了以下进展： 1）发展了准经典动力学和Ring-Polymer Molecular Dynamics （RPMD）动力学方法，系统并精确地研究了燃烧中重要化学反应的反应微观机理以及速率常数，为燃烧机理的模拟提供了重要理论依据；2）对重要的双分子燃烧反应H +C2H4->H2+ C2H3开展了高精度的理论计算研究，揭示了该反应中新奇的碰撞诱导漫游机理；3）发展了基本不变量-神经网络拟合方法构建多原子反应体系的精确绝热势能面，通过高精度从头算构造了H+H2O2, OH+HO2, H+C2H4等反应体系目前最精确的势能面；4) 发展了高效且精确的神经网络方法构建透热表象下具有锥形交叉的耦合势能面，通过多参考组态从头算构造了目前最为精确的ClH2、 NH3、H3、H3+等体系的透热势能矩阵，为多原子反应的非绝热动力学研究打下基础。资助期间，以第一作者/通讯作者共发表SCI文章21篇，包括1篇 Chem. Soc. Rev., 1篇Chem. Sci., 1篇JPCL等。