Quasiclassical Trajectory Calculation Of The Chemical Reaction Ba+CHCl₃, Ca+CF₃I, Ba+SiCl₄

Molecular reaction dynamics is a subject of analyzing the mutual movement and the interaction between the molecules, based on the atomic and molecular properties. Molecular reaction dynamics is based on the experimental measurement and theoretical calculation, these two methods led to the rapid development of molecular kinetics. At present, the main experimental methods include the Crossed Molecular Beam, infrared Chemiluminescence (CL), Laser-induced Fluorescence (LIF) and Resonance-enhanced multiphoton ionization. The main theoretical calculation methods include the quasi-classical trajectory (QCT) method, quantum theory method and the semi-classical method.The quasi classical trajectory method is used in this thesis. Based on the molecular collision of classical mechanics, the quasi-classical trajectory method is used to simulate the movement of reactants on the potential energy surface, by solving Hamiltonian canonical equations. The advantage of this method is that the calculation is simple and the results are more accurate, avoiding the complex numerical calculations of quantum mechanics. Thus, quasi-classical trajectory method has gradually been accepted and widely used in many chemical reaction systems. Finally, it has become an important method in micro chemistry research.In this paper, the structure of London-Eyring-Polanyi-Sato(LEPS) ’quasi-three-body’potential energy surface is constructed, the reactions of Ba+CHCl3、 Ca+CF3I and Ba+SiCl4 are studied with the quasi-classical trajectory method. The results of the product vibrational distribution, the reaction cross section, the rate constant and other kinetic information were obtained through a large number of trajectory calculations. For this three reactions, there exists a reaction barrier or a potential well existing in the LEPS PES. The results of vibrational distribution first increases to its maximum value and then decreases with the increasing of vibration quantum number v, the peak appeared at v=33, v=10, v=39, respectively. All of the rate constants increase with the increasing of the temperature. The relationship between the product rotational alignment and the collision energy largely depends on the type of mass combination of the reaction.The experimental study of molecular reaction dynamics is helpful for the understanding of the reaction mechanism. The theoretical calculation is to further deepen the understanding of the entire reaction system on the basis of the experiment, and it is advantageous to control and use the chemical reaction. From these three results it can be seen that it is feasible to use the quasi-classical trajectory method to simulate and explain the experimental results.