Born–Oppenheimer and Renner–Teller coupled-channel quantum dynamics of the N(D2)+HD reactions

Abstract

We present the Born-Oppenheimer (BO) and Renner-Teller (RT) coupled-channel dynamics of the N((2)D) + HD --> NH + D and N((2)D) + HD --> ND + H reactions, considering the X (2)A(") and A (2)A(') states and RT and Coriolis couplings. We use the best available potential energy surfaces and obtain initial-state-resolved probabilities, cross sections, and rate constants via the real wave packet and flux methods for both electronic states. In contrast with the RT results of BO-X (2)A(") ones, we point out the role of RT and Coriolis interactions for both reactions and discuss the importance of the excited state on the initial-state-resolved dynamics and on the thermal kinetic rate. Moreover the competition for the formation of two products is discussed, showing some snapshots of the RT wave-packet density on the ground state. However, the BO approximation gives thermal rates that are smaller than those obtained via full RT calculation, especially at 300 K. Our calculated RT rate constants at room temperature are in good agreement with the experimental ones. The branching ratio is also calculated at T = 150-300 K at BO and RT levels. At 300 K the calculated value overestimates slightly the experimental data.