Study Of The Stereodynamics For The O(~1D)+H/DBrâ†'OH/D+Br Reaction

With the rapid development of science and technology, great improvements have also been made on the study of molecular reaction dynamics, and kinetic molecular reaction dynamics, as a part of it, has also got much attention from science and technology workers. Nowadays, with the mutual development and promotion of theoretical and experimental researches, the study on chemical reactions has gradually penetrated into the field of state-state researches. In atmospheric chemistry, the O(1D) +HBr→OH+Br reaction and its isotopic reactions which the oxygen atoms and bromine atoms participate in have been widely concerned by experimental and theoretical workers. However, most of their reactions are confined to the research on the scalar quality of the reaction process, lack of critical vector-related dynamic information. In this research, with the adoption of the quasi-classical trajectory method, the three-dimensional dynamics quality of O (1D)+HBr→OH+Br reaction and its isotopic reactions are investigated and discussed in depth.In this research, with the combination of quasi-classical trajectory method and Peterson ab initio potential energy surfaces in the center of mass coordinate system, the integral cross section, differential cross section, polarization differential cross section, and the relationship of the relative velocity vector and angular momentum vector of O(1D)+HBr→OH+Br reaction and its isotopic reactions O(1D)+DBr→OD+Br are calculated in detail at different collision energy and vibration quantum number, and the results indicate that:(1) In different collision energy case, the existence of a well on the potential energy surface leads to the forward and backward scattering of 0 (1D)+HBr→OH+ Br reaction cross sections; the function distribution of k-k'-j' three-vector correlation shows that, the O (1D)+HBr→OH+Br reaction not only has the orientation effect along the Y axis, but also has the orientation effect along the positive of Y axis. (2) In different vibration quantum number cases, the result of O (1D)+HBr→OH +Br reaction cross section and polarization distribution shows that the vibration quantum number has a relatively large impact on the polarization distribution of the chemical reaction.(3) In single collision energy case, the calculation results of O (1D)+DBr→OD+ Br reaction indicate that the polarization of the product tends to molecular scattering plane; reaction cross sections also show significant forward and backward scattering; the change of collision energy's impact on reaction is also very obvious.(4) The comparison between the O (1D)+HBr→OH+Br reaction and isotope reaction O (1D)+DBr→OD+Br reveals that the isotope effect is obvious in kinetic molecular reaction dynamics.