Quasiclassical Trajectory Calculation On The Reaction F+H₂

Molecular reaction dynamics is one to investigate the chemical reaction process and mechanism of different states for different molecular systems on micro level of molecules or atoms. Up to now, based on rich experimental results, appropriate theoretical model and accurate dynamical calculations, a large amount of micro chemical reaction dynamical information has been obtained, and the reaction mechanism for micro chemical reaction has been recognized and comprehended deeply and thoroughly.Quasiclassical trajectory calculation is one of the effective methods for solving atomic and molecular collision reaction dynamics, it provids definite physical meaning and intuitionistic images by using trajectory to describe reaction system along with time, based on solving the Hamiton equations of motion to solve the movement of atomic nucleus on potential energy surface, This method is rather simple, intuitive.The computed result is quite accurate,also it has avoided the complex quantum mechanics Numerical process, therefore it has already been applies on many chemical reaction systems,and becomes an important method in the research on microscopic chemical reaction. Through the trajectory computation, we can obtain the reactant energy state, the reaction cross section, the excitation function,the product energy partition,the energy state distribution,the rotational alignment and the spatial angle distribution as well as the velocity distribution and so on a Large Amount of datas. For a reaction system with given initial configuration,It can reveal the chemical reaction microscopic mechanism through the research on internal energy distribution of product.The quasiclassical trajectory was used in this article to compute the system H2+F→HF+H with the London-Eyring-Polanyi-Sato(LEPS) potential energy surface. The calculation indicate that, in this reaction,two pathways are involved,one is the abstraction ,the other is the insertion,and the Formation Mechanism of the two were discussed. The ratio of abstraction increase along with the increasing collision energy, reactant in the vibration excited state can strengthen this kind of pathway compare with in the vibration ground state.The reaction alignment is concerned,the product rotational angular momentum vector about the relative velocity alignment is strenghten along with the increacing energy.Because the product rotational angular momentum vector distribution is extremely sensitive to the quality factor for three atomic reaction system,when the quality factor is small, the reactant orbital angular momentum and the majority of available energy was transformed into the product rotation angular momentum and the internal energy,the ratio of product orbital angular momentum and reactant orbital angular momentum correspondingly reduce along with the increasing collision energy,therefore the product rotation angular momentum vector has the intense alignment about the relative velocity vector.The paper can be divides into four chapters.First chapter is the summary, it introduced the questions need to be solved in molecular reaction dynamics,and the theories which were developed in solving questions of molecular reaction dynamics.the Second chapter introduced the principle, the computational method, the various data of product after quasiclassical trajectory claculation, as well as the principle of LEPS potential energy surface.The third chapter, based on the system we studied, the Formation Mechanism of the two kinds of pathway and the influence on the reaction while with different initial conditions were discussed,and reaction alignment was calculated with the changing energy.Fourth chapter is the conclusion, make a summary about content involved in this article.