Effect of Rotational Excitation on Stereodynamics for the Reactive Collision Between N(²D) and H₂

Effect of rotational excitation on stereodynamics for the N( ²D)+H₂(v=0, j=0−5)→NH(v', j')+H collision reactions is investigated by employing the quasiclassical trajectory method. Based on an accurate 1²A" potential energy surface, three angular distributions P(θ_r ), P(φ_r ), P(θ_r,φ_r ), and polarized−dependent differential cross section 2π/σ dσ₀₀ /dω_t are calculated at a collision energy of 5.1 kcal/mol. It is found that the P(θ_r ) distribution has a distinct peak at about θ_r=90°. The P(φ_r ) distribution has a small peak at about φ_r=270° and no peak at about φ_r=90°. This implies that the product angular momentum j' is not only aligned perpendicular to k, but also orientated to the negative direction of the y axis. The product rotational alignment and orientation become increasingly weaker with an increase of the rotational quantum number j of H₂. Analysis of trajectory propagation demonstrates that the title collision reaction has a dominant indirect insertion mechanism and a minor direct H-abstraction mechanism.