Effects of Initial Molecular Alignment on the Stereodynamics of the H + Cl2(v = 0, j = 1) → HCl + Cl Reaction

Using the time-dependent wave packet method, we reveal pronounced stereodynamical effects in the H + Cl2(v = 0, j = 1) reaction with initially aligned Cl2. Rather than acting as a simple steric factor, the initial collision geometry controls the interference among K0 components and selects different J-resolved reaction pathways. In the incoherent limit, the β = 0° geometry dominates over most collision energies because low-J partial waves favor the K0 = 0 component, whereas the β = 90° geometry becomes important near 1 eV as high-J, |K0| = 1-related channels open. Including interference between K0 components suppresses the β = 45° reactivity but strongly enhances the β = 90° reactivity. DCSs and GDFs further reveal an alignment-dependent redistribution of J-resolved partial waves, favoring backward scattering for β = 0° and 45° but side-backward scattering for β = 90°.