Theoretical Study Of Coriolis Coupling And Isotope Effect In Triatomic Reaction Systems

The effects of coriolis coupling and isotopic effect are important parts of the kinetic theory of molecular reaction systems.A large number of studies have proved that the effect of coriolis coupling and isotope effect is very significant in the reaction systems,especially in some small molecular systems.and their role cannot be ignored.As the representative of light-heavy-light triatomic reaction,the influence of coriolis coupling and isotope effect is worth exploring in Li+HCl system and S+H₂ system.A large number of scientific calculations have proved that the potential energy surface with high accuracy is the basis of the study of reaction system dynamics.Therefore,based on the recently published high-precision potential energy surface of Li+HCl reaction system and S+H₂ reaction system,this paper used time-dependent quantum wave packet method to carry out kinetic studies on these two triatomic reaction systems,and further discusses the influence of coriolis coupling effect and isotope effect on the reaction system.The specific work includes the following parts:In the first part,the introduction and development of molecular reaction kinetics are briefly introduced,and then the theoretical research and development of the influence of coriolis coupling and isotope effect in the reaction system are analyzed.The second part mainly detailed introduces the research on the theory of three atoms reaction kinetics,describes the time-dependent quantum wave packet method in the calculation of the main content:from the wave function expansion,the construction of the initial wave packet and transmission,the wave packet contact reaction border processing,introducing absorption potential coriolis coupling effect and the difference between the centrifugal potential approximation,and finally to the time-dependent quantum wave packet method output observable quantities of data processing are made detailed instructions.The third part,based on the time-dependent quantum wave packet method and the high-precision potential energy surface of Li+HCl reaction system,calculates the reaction probability,integral cross section and reaction rate constant under the action of coriolis coupling effect and centrifugal potential approximation of Li+H（D）Cl system,and compares the reaction rate constant obtained in the experiment.Calculation results show that the coriolis coupling effect and isotope effect on Li+H（D）Cl system has a very important role in the reaction,the coriolis coupling effect in a certain extent,can promote the reaction,and the introduction of the isotope make the direct reaction mechanism in the reaction system insert reaction mechanism,the increase in the reaction system in the transition state of reactants in the middle of the produce complex survival time,has weakened Li+H（D）the probability of occurrence of Cl system.At the same time,the influence of vibrational excitation state on the Li+H（D）Cl system is analyzed.The results show that the high vibrational excitation state can effectively promote the reaction of Li+H（D）Cl system.In the fourth part,the high-precision potential energy surface of S+H₂ reaction system is studied by time-dependent quantum wave packet method.In this study,the reaction probability curve,reaction section and reaction rate constant of S+H₂ reaction system under coriolis coupling and centrifugal potential approximation are calculated.At the same time,the reaction probability of S+H₂ reaction system under different excitation states is calculated.The results show that the coriolis coupling effect and isotope effect have great influence on the title reaction.The coriolis coupling effect can effectively promote the occurrence of title reaction,because the substitution of heavy element D increases the time of reactant passing through the transition state in the reaction system,which weakens the occurrence of title reaction.The higher vibrational excitation state plays a positive role in promoting the title reaction.The last part shows the main research results of this paper and makes a prospect on the basis of this work.