Detailed Quasi-Classical Dynamics of the F– + SiH3I Multi-Channel Reaction

We extend our previous quasi-classical trajectory study of the multi-channel F– + SiH3I reaction on a full-dimensional analytical potential energy surface over the collision-energy range of 1–80 kcal/mol. We combine reaction probabilities and integral cross sections with initial attack-angle, scattering-angle, and product-energy distributions to characterize the major and low-probability reaction channels. Iodide substitution is the dominant reaction throughout this range, followed by proton abstraction. At low collision energies, substitution is capture dominated and strongly favors Walden inversion. At higher energies, inversion and retention cross sections become comparable, while forward scattering becomes more pronounced, particularly for inversion. Proton abstraction changes markedly with collision energy: forward scattering increases, and the product translational-energy distribution shifts toward higher energies, consistent with an increasing contribution from direct stripping. In contrast, hydride substitution and several multistep minor channels show stronger internal excitation. Taken together, these results reveal distinct collision-energy-dependent mechanisms and energy-partitioning patterns among the reaction channels of the title system.