Theoretical Study Of Molecular Dynamics Of The Three-atom Collision Reaction O+HH By Quasiclassical Trajectory

Molecular reaction dynamics is a cross branch of learning between chemistry and physics, which is also a science of studying microcosmic dynamic and mechanism of chemical reaction in molecular and atomic level. Hence, it can be seen as a bridge connecting microcosmic dynamics and macroscopical dynamics. As a new branch of molecular reaction dynamics, stereodynamics mainly investigates vector properties of microcosmic chemical reaction, and then gives a complete chemical reaction image by a combination with scalar properties.The first chapter of this paper is summarization of the literature, introducing the origin and current situation of molecular reaction dynamics, stereodynamics and quasiclassical trajectory (QCT). In chapter Two. it firstly introduces potential energy surface (PES) which plays an important role in molecular reaction dynamics and stereodynamics and then introduces the computing theory of QCT mentioned in the summarization and vector correlation involved in the results and discussions.It applies QCT method to study the reaction0(3P)+H2(v=0, j=0)â†'OH+H on the3A’and3A" PESs in chapter Three. Information of the vector correlations revealing the product alignment and orientation on the two different triplet PESs has been provided. The results of the calculations show that the products not only align strongly along the direction perpendicular to reagent initial relative vector k. but also orient along the direction of the negative y-axis, with stronger product polarizations being observed on the3A" PES at the collision energy smaller than24kcal/mol and on the3A’PES at the collision energy bigger than24kcal/mol. On both PESs. especially on the3A" PES, the products show preference for backward scattering which becomes weaker as collision energy increases. In chapter Four, it uses the same method to calculate the isotope reaction of the title reaction by exchanging H atom into D atom. The conclusion is that on the3A’PES the isotope effect of the product rotational alignment is more obvious than that on the3A" PES while the isotope effect of the product orientation and the PDDCSs are more obvious on the3A" PES. In chapter five, we aim at investigating reagent’s rotational and vibrational excitations on the product stereo-dynamics. The reaction cross-section is considered as the only scalar property that appears in this work at four different collision energies. Furthermore the vector properties including two of the distributions of the polarization-dependent differential cross sections (PDDCSs), the angular distributions of the product rotational momentum P(θr) and P((?)r) are discussed at one fixed collision energy. The effects of the reagents’rotational excitation on the reaction do exist regularly.