Fragmentation pathways and chlorine Release from CHF₂cl under EUV and soft X-ray ionization

The dissociation pathways of difluorochloromethane (CHF 2 Cl) induced by EUV and soft X-ray photons were investigated using PEPICO spectroscopy and MCSCF calculations. Kinetic energy release distributions (KERDs) extend from quasi-thermal (≈ 0.02 eV) to ≈ 4 eV, evidencing both statistical and prompt dissociation pathways. Multimodal KERDs highlight competing mechanisms linked to distinct electronic states, whereas chlorine release is strongly enhanced near the Cl 2p edge through both Cl-centered ionization and the excitation of fluorine orbitals, underscoring electronic delocalization. Crucially, the methodology for extracting 〈KER〉 and KERDs from PEPICO spectra is well established, ensuring reliable quantification of fragment energy distributions. Furthermore, FWHM analysis distinguishes resonance-driven broadening in atomic fragments from stable molecular ion channels, revealing the coexistence of different fragmentation regimes. Altogether, these results provide a comprehensive framework of halocarbon photofragmentation under high-energy radiation, with significant implications for molecular pathways and atmospheric chemistry.