大气汞氧化还原过程与机制的计算化学研究进展

大气中汞的氧化还原反应对于其全球生物地球化学循环起着极其重要的作用,它促进了汞在全球范围内的扩散.汞主要以气态元素汞的形态释放到大气中,并经历复杂的均相和非均相化学反应,被氧化为活性气态汞和颗粒态汞;同时,活性气态汞也可经过光致还原反应光解生成气态元素汞.计算化学是一种基于理论方法利用计算软件来对化学现象和本质进行解释...

Advances in computational chemistry for oxidation and reduction of mercury in the atmosphere

The redox reactions of atmospheric mercury play an important role in the biogeochemical cycle of mercury.Mercury is mainly released into the atmosphere as gaseous elemental mercury(GEM),which undergoes complex redox reactions to be oxidized to reactive gaseous mercury(RGM)and particulate bound mercury(PBM).Meanwhile,RGM also can be photolyzed to GEM.Computational chemistry is an approach covering any use of computing in the direct study of chemical problems,which is widely used in studying the mechanism of atmospheric mercury redox reactions.This review summarizes the theoretical studies of the oxidation mechanism of GEM by common atmospheric oxidants such as O₃,·OH,NO₃ and halogen radicals,including bond dissociation energy,transition states,rate constant and so on.Meanwhile,this article also reviews the photodissociation mechanisms of RGM based on high-level quantum chemical methods,including the UV-Vis absorption spectra and cross-sections of RGM,two-dimensional potential energy surfaces,photodissociation yields and photolysis rates.Understanding the theoretical studies on the photochemistry of mercury in the atmosphere is helpful to understand the global atmospheric mercury distribution,transport,and lifetime.