Influence of collision energy on cross section and stereodynamical properties for the reaction H+OCl→OH+Cl

Stereodynamic study of the reaction H(²S) + ClO(²Π) → HO(²Π) + Cl(²P) via quasi-classical trajectory calculations

Quasi-classical trajectory calculations were performed to investigate the stereodynamics of the reaction H(²S) + ClO(²Π) → HO(²Π) + Cl(²P) using the ground-state potential energy surface 1¹A'. The alignment and orientation of the product molecules as well as the four polarization-dependent differential cross-sections (PDDCSs) for this reaction across a wide range of collision energies (0.05-1.0 eV) and for the rovibrational state ClO(v = 0 and j = 0) were obtained and are reported here. It was found that the OH product rotational polarization is not very sensitive to the collision energy selected. We discuss this phenomenon in detail. The calculated results indicate that, for this system, the two deep wells in the potential energy surface are very likely to be powerful influences on the degree of product rotational polarization. In addition, the microscopic reaction mechanism that dictates the product angular momentum orientation was investigated. The forward peak in the PDDCS₀₀ at θ = 0° in our study showed a strong dependence on the initial collision energy.

Reagent vibrational, rotational and isotopic effects on stereodynamics of the H + OCl → OH + Cl reaction

The quasi-classical trajectory method has been employed to investigate the initial vibrational and rotational effects of the title reaction on an improved ab initio potential energy surface for the 11A′ state. Meanwhile, isotopic effect has also been studied at collision energy of 19 kcal/mol. The product rotational alignment factor 〈P2(j′ • k)〉, angular distributions of P(ϕr), P(θr) and the generalized polarization dependent differential cross-sections have been calculated. The- results show that the reagent vibrational excitation generally strengthens the product alignment perpendicular to the reagent relative velocity vector k and affects the product scattering preference, and the rotational excitation has the same trend from j = 0 to 2 except for the higher excitation of j = 3. Further, the substitution of atom H with D leads to a stronger product alignment while changes some stereodynamical properties subtly.

Quantum wave packet and quasiclassical trajectory studies of the reaction H(2S) + CH(X2 Π; v = 0, j = 1) → C(1D) + H2 (X1 Σg+): Coriolis coupling effects and stereodynamics

The quantum mechanics (QM) and quasiclassical trajectory (QCT) calculations have been carried out for the title reaction with the ground minimal allowed rotational state of CH (j = 1) on the 1 (1)A' potential energy surface. For the reaction probability at total angular momentum J = 0, a similar trend of the QM and QCT calculations is observed, and the QM results are larger than the latter almost in the whole considered energy range (0.1-1.5 eV). The QCT integral cross sections are larger than the QM results with centrifugal sudden approximation, while smaller than those from QM method including Coriolis coupling for collision energies bigger than 0.25 eV. The quantum wave-packet computations show that the Coriolis coupling effects get more and more pronounced with increasing of J. In addition to the scalar properties, the stereodynamical properties, such as the average rotational alignment factor <P2 (j'•k)>, the angular distributions P(θr ), P(ϕr ), P(θr ,ϕr ), and the polarization-dependent generalized differential cross sections have been explored in detail by QCT approach.