Quantum dynamics of O(1D)+D2 reaction: isotope and vibrational excitation effects

The effect of initial vibrational excitation of the D-2 molecule on the quantum dynamics of the O(D-1)+D-2 reaction is investigated as a function of collision energy. The potential energy surface of Dobbyn and Knowles (1997 Mol. Phys. 91 1107) and a time-independent quantum mechanical method based on hyperspherical coordinates have been adopted for the dynamics calculations. Results for elastic, inelastic, and reactive scattering over collision energies ranging from the ultracold to thermal regimes are reported for total angular momentum quantum number J = 0. Calculations show that the collisional outcome of the O(D-1)+D-2 reaction is not strongly influenced by the initial vibrational excitation of the D-2 molecule similar to its H-2 counterpart. A J-shifting approximation is used to calculate the initial state selected reactive rate coefficients over the temperature range T = 1-500 K. The reactive rate coefficients for D-2(nu = 0) are found to be in excellent agreement with available experimental results. The temperature dependence of the kinetic isotope effect is also investigated and its value at room temperature is found to be in good agreement with available theoretical and experimental results.