Vibrational State-Resolved Differential Cross Sections of the F + CH₄ → HF + CH₃ Reaction at the Collision Energies of 3.1–13.8 kcal/mol

We report a high-resolution crossed molecular beam experiment investigating the reaction dynamics of the F + CH₄ → HF + CH₃ reaction across a broad range of collision energies (3.1–13.8 kcal/mol). By using time-sliced velocity map imaging within the crossed molecular beam apparatus, we obtain correlated angular distributions and branching ratios for various product pairs (CH₃(ν), HF(ν′)). The resolved reactive rainbow-like features that display a distinct bulge in the angular distribution in different channels reveal the formation of vibrationally ground and excited states of the methyl radical accompanied by different rovibrationally excited HF products. These findings suggest distinct reaction dynamics for channels leading to vibrationally excited methyl radicals compared to those forming ground-state methyl radicals.