Theoretical Study Of The Stereodynamics Of The Reactions Of He+H₂⁺ And Its Isotopic Variants

As a new frontier branch in molecular reaction dynamics fields, the dynamics stereochemistry to the study of the vector properties of micro-chemical reaction mainly relate to the chemical reaction of the vector correlation, as well as the problem of reactants and products spatial orientation. In recent decades, with the development of theory and experiment, the dynamics stereochemistry has rapidly developed into a hot area. Study of the vector properties can find the dynamics of information which is lost only considering scalar properties. Only by considering the scalar and vector properties together, the micro-chemical reaction process can be more comprehensively understood and thus the fullest picture of the scattering dynamics be obtained. In this paper, theoretical study of the stereodynamics of the reactions of He+H₂⁺and its isotopic variants have been carried out using the quasi-classical trajectory (QCT) method.The outline of the molecular reaction dynamics and dynamics stereochemistry, together potential energy surface (PES) of reaction systems are given in the first chapter of this paper. The vector correlation and related theories of QCT are given a brief introduction in chapter two.The study of stereodynamics for the reactions of He+H₂⁺/ He+HD+ /He+HT+ have been calculated by QCT method based on Palmieri et al in chapter three. The results indicate that the degree of product rotational polarization becomes weaker as the mass factor increases and the isotopic effect on the correlated k-k′-j′angular distributions also had a significant impact. In addition, the reactions are sensitive to the repulsive energy of diatomic molecule.In chapter four, the vector correlation in the reactions of He+H₂⁺(Ï…=0-2, j=0) have been performed on the above PES. The results show that the correlated k-j′, k-k′-j′angular distributions, and the polarization dependent differential cross-sections (PDDCSs) are particularly sensitive to the vibrational excitation of the reactant molecular ion. In the calculation, the collision energy can be the same, these discrepancies may be ascribed to the vibrational number of the reactant molecular ions.The theoretical study of the He+H₂⁺ reaction has been carried out on two PESs in chapter five. The results calculated indicate that the rotational polarization of product presents different characters on both PESs. At the same collision energy, it may be ascribed to the different constructions of the two PESs.And in chapter six the vector properties of the chemical reactions He+D ₂⁺ / He+T ₂⁺ and He+D₂⁺ (Ï…=0, j=0-2) have been studied at different collision energies and same collision energy, respectively. The results show that collision energy has produced a greater effect on the spatial distribution of the product for the reactions of He+D₂⁺ / He+T ₂⁺ . In particular, we found that the increase of collision energy reduces the degree of anisotropic distribution of product rotational angular momentum vector j′. The role of collision energy is also very obvious to the correlated k-k′-j′angular distributions and PDDCSs. In addition, the rotational excitation of the reactant molecular ion also has a certain influence for the product distribution of He+D₂⁺ reaction.Finally, a brief summary and prospect of this paper are given in chapter seven.