Stereodynamical Control on the Br (²P_3/2, ²P_1/2) + H₂ (v = 0, j = 1) → HBr + H Reactions

The stereodynamical control of collision partners can profoundly influence the reactive scattering result. This study investigates the stereodynamical control of the Br (²P_3/2, ²P_1/2) + H₂ (v = 0, j = 1) → HBr + H reactions using the time-dependent wave packet method, by manipulating the alignment angle β between the bond axis (described by both the azimuth angle α and polar angle β) of the rotationally excited H₂ molecule and the relative velocity of the collision partners. A two-state model is used for the calculations. Analysis of the integral scattering cross sections reveals that both β = 0° and β = 90° configurations enhance reactivity, whereas β = 30, 45, and 60° configurations show inhibitory effects. Differential cross sections show that the β = 90° configuration enhances the sideways scattering of both reactions, while the β = 0° configuration is more preferred for inducing backward scattering. The analysis reveals that backward scattering products can be obtained in the excited spin-orbit state reaction by head-on collisions in the low collision energy region, and sideways scattering products can be obtained in the high collision energy region by side-on collisions. In contrast, the direction of scattering is more easily controlled at the high collision energy region in the ground spin-orbit state reaction. In the present work, we also further reveal the crucial role of interferences in the stereodynamical control of the reactions when the differential cross sections are observed.