气溶胶表面的非均相反应不仅改变了原来颗粒物的组成，而且还会增强颗粒物的吸湿性、增大粒径和消光效率，从而降低大气能见度，促进灰霾的形成。多环芳烃具有"三致"效应，是大气中的重要污染物之一。含三个以上苯环的多环芳烃易附着于碳质颗粒物和砂尘等大气颗粒物表面进行气-固非均相反应，生成硝基多环芳烃和含氧多环芳烃衍生物等致癌性和诱变性更强的污染物。本项目拟采用高精度量子化学计算研究多环芳烃在石墨、SiO2和蒙脱土等表面的非均相反应。探讨反应路径、中间产物及相应的动力学、热力学性质，找到主要反应通道、速控步骤；在量子化学计算提供的势能剖面基础上，采用直接动力学方法计算非均相反应过程中包含的基元反应的速率常数；阐明多环芳烃中苯环数目及相对空间位置对多环芳烃反应活性的影响；为有效控制环境空气污染以及治理大气污染和环境立法、环境规划提供理论依据和科技支撑。

The heterogeneous reaction taken place on the surface of areosols can change the composition and enhance the hydrophilicity, grain size and extinction efficiency of paticulte matters, thus attenuate atmospheric visibility and facilitate haze formation. PAHs(polycyclic aromatic hydrocarbons) are important atmospheric contaminants with significant carcinogenic and mutagenic properties. Due to their high affinity of carbonaceous particulate matters and sands, PAHs containing three or more aromatic rings can undergo gas-solid heterogeneous reactions on atmospheric pariculate matters. Heterogeneous reactions of particulate PAHs is an important pathway of their atmospheric degradation often leading to the formation of nitro-PAHs and oxygenated-PAHs which are even more toxic and mutagenic compounds than primary PAH molecules.This project will study the heterogeneous reactions of PAHs on the surface of graphite, SiO2 and montmorillonite by applying high-accuracy quantum chemical calculations.The pathways,intermediates and other thermodynamical parameters will be investigated from the molecular level. The dominant pathways and the rate-determining steps will be obtained from this study.On the basis of the profiles of the potential energy surface obtained from the quantum chemical calculation, the rate constants of the elementary reactions involved in the heterogeneous reactions of PAHs will be calculated with the aid of the direct dynamical methods.This project will also study the influence of the number and position of the aromatic ring in PAHs on the reactivity of PAHs.We hope that this project will help to develop more effective control strategies of the air pollution and be of practical value for the environmental planning and environmental legislation.This study would like to provide a contribution for the atmospheric chemistry.