Theoretical Studies Of The Stereodynamics For The Reaction H+LiH⁺�'Li⁺+H₂

Molecular reaction dynamics, which is also named microscopic chemical kinetics, is an object of studying mechanism and microscopic feature for chemical reaction on molecular and atomic level. With the high development of the experiment and theory, great accomplishments have been made in molecular reaction dynamics area, which has gotten to a new state-to-state chemical dynamics stage. As a new field of the molecular reaction dynamics, dynamical stereo-chemistry has offered more detailed information for the microscopic reaction. Quasi-classical trajectory method is the most important method for the dynamical stereo-chemistry. In the thesis, theoretical studies of the stereodynamics for the chemical reaction H+LiH+→Li++H2 have been studied via the quasi-classical trajectory (QCT) method.For the reaction H+LiH+→Li++H2, because of the existence of the weak Van der Waals wel lying in the product valley, there is a short-lived collision complex, which leads that the forward-backward scattering is asymmetry. In the first place, we have studied the stereodynamics of the reaction H+LiH+(v=0, j=0)→Li++H2 at three collision energies, 0.01,0.05 and 0.1eV. The result of the DCS indicates that reaction prefers to forward scattering as collision energy increases. The calculated P(θr)shows that the product molecule rotational angular momentum polarization is quite strong and the product molecule rotational angular momentum polarization is insensitive to the increasing of the collision energies. When the collision energies change from 0.01 to 0.05eV, the reaction mainly behaves as an exoergic reaction rather than an insertion mechanism. While the distributions of P(φr) indicate that product molecule rotational alignments j'is not only aligned, but also oriented preferentially along the positive direction of the Y-axis. The orientation along the positive direction of the Y-axis enhances with the collision energy increasing. Subsequently, we also studied the stereodynamics of the reaction H+LiH+(v, j)→Li++H2 in different initial vibrational and rotational levels at the collision energy of 0.03eV. The results show that the reaction prefers to forward scattering with the increasing of the initial vibrational level. However, the distribution of the product scattering is insensitive to the increasing of the initial rotational level. We also calculated the distributions of P(θr) and P(φr). The results indicate that the polarization, alignment and orientation of the product molecule rotational angular momentum have some dependence for the initial vibrational level, while they are insensitive to the increasing of the initial rotational level. The reaction prefers to behave as an exoergic reaction with increasing of the initial rotational level, while the mechanism of reaction is insensitive to the increasing of initial vibrational level.