Collision Reaction Internal Energy Distribution And Vector Correlations By The Quasiclassical Trajectory Method

In order to understand the dynamics of atom and molecule collision reaction fully, it is important to study not only its scalar properties, but also its vector properties. The vector property of chemical reaction can provide valuable information about chemical reactive stereodynamics. In recent years, stereodynamics, focused on the research of correlation of angular momentum and other vectors in the process of reaction, was developed and has made a great achievement in both theories and experimental methods. Only by understanding together the above properties can the fullest picture of the scattering dynamics emerge. Quasiclassical trajectory (QCT) method is one of the most important ways to investigate molecular reaction dynamics. In this thesis, the stereodynamics of several typical reaction system including Ca+RBr(R=CH₃, C₂H₅, n-C₃H₇), N+NO, N+O₂ and C+NO reactions have been studied using the QCT method.The outline of the molecular reaction dynamics and stereodynamics, together potential energy surface (PES) of reaction systems are given in introduction section. The related theories of QCT and vector correlation are introduced in chapter one and two, respectively.The internal state distribution of product CaBr in the reactions Ca+RBr→CaBr + R (R= C₂H₅, n-C₃H₇) are studied using QCT method based on the extended LEPS PES in chapter 3. Research shows that the fractional energies disposed into translation and rotation of the CaBr product increase, accordingly vibrational fraction decreases as the collision energy increases. This result can be attributed to two competitive reactive pathways existing during the reaction. Vector properties about these reaction systems were studied in chapter 4. The QCT calculated rotational alignment of product is accord to the experimental results. The product angular momentum vector is not only aligned, but also oriented along the -y axis and the alignment degree of product become weak as the radical R increases. In chapter 5-7, the vector correlation and product rotational alignment are investigated using QCT method based multi-body expansion analytical PESs for three reaction systems ((N(⁴S)+O₂( X³ÃŽÂ£_g^- )→NO(X²ÃŽÂ )+O(³P), N(⁴S)+NO(X²ÃŽÂ )→N₂( X³ÃŽÂ£_g^-)+O(³P), C(³P)+NO(X²ÃŽÂ )→CN(X²ÃŽÂ£⁺)+O(³P))). The three reaction systems play an important role for understanding of the NO reburning. The research shows that the product rotational angular momentum vector is aligned and oriented, the direction of orientation depends on the collision energy. These...