Theoretical Study On Stereodynamics Of H+NeH~+and H’+Hs Reactions

Stereodynamics focusing on the research of the correlations of angular momentum and other vectors in the processes of chemical reaction has developed and made a great achievement in both theoretical and experimental aspects. In this thesis, dynamics especially stereodynamics of reactions H+NeH+and H’+HS have been investigated by the quasi-classical trajectory method.Based on the lasted constructed ab initio potential energy surface(PES) by LV et al, the reaction dynamic properties of H+NeH+(v=0,j=0)â†'H2++Ne and its isotopic reactions on the ground state PES have been studied and the mechanisms have been deeply explored. The results indicate that direct reactive mechanism is dominant in these reactions. Some amounts of backward scattering indicate that indirect reactive mechanism may play a role due to the existence of a well on the PES. However, such phenomenon only occurs at low collision energies. With the increasing of the collision energy, the tendency of forward scattering increases quickly and the backward scattering decreases. The product angular momentum j’is not only aligned, but also oriented along the positive direction of y axis, showing its strong polarization. Isotopic effect on the stereodynamics of the reaction H+NeH+shows that the alignment of j’ is mainly determined by the mass factor on the same PES. Moreover, the initial internal energy states of reagent molecules have significant influence on the vector properties. With the increasing of vibrational excitation, the degree of backward scattering becomes weaker while the polarization of j’becomes stronger. Yet the enhancement of rotational excitation leads to the decline in both forward and backward scattering together with the decrease of the polarization of j’. For the reaction H’+HS, the reaction dynamic properties for the abstract reaction channel H’+HS(v=0,j=0)â†'H2+S and the exchange reaction channel H’+HS(v=0, j=0)â†'H’S+H have been studied on the ab initio PES constructed by LV et al. For the abstract reaction, when collision energy increases, the alignment of j’ has a slight increase and its orientation along the negative of y axis declines substantially. And for the exchange reaction, the degree of alignment and orientation of j’simultaneously increase with the strengthening of the collision energy.