From Energetics to Intracluster Chemistry: Valence Photoionization of Trifluoromethylsulfur Pentafluoride (CF₃SF₅) by Double Velocity Map Imaging

Trifluoromethylsulfur pentafluoride (CF3SF5) was valence threshold photoionized in a double imaging photoelectron photoion coincidence spectrometer using vacuum ultraviolet synchrotron radiation. In the 12.5-16.4 eV photon energy range, CF3+, SF5+, and SF3+ cations were observed both room temperature (RT) molecular beam (MB) experiments. Their fractional abundances exhibited differences beyond sample temperature. Kinetic analysis of fragment ions confirmed difference dissociative photoionization mechanism. RT experiment, CF3+ kinetic energies extrapolated to 11.84 ± 0.15 threshold, which used an ion cycle determine enthalpy formation CF3SF5 as ΔfH°298K(CF3SF5) = -1593 16 kJ mol-1. We also updated sulfur radical ΔfH°298K(SF5) -854 7 mol-1 discuss discrepancy between CF3 ionization based on Active Thermochemical Tables value anchored CF energy. A computed reaction network optimization resulted -1608 20 Both values for agree with previous ab initio ones contrast original, experimental determination. is formed by F-transfer processes MB Although same peaks experiments, lower onset more slowly rising release experiment revealed clustering intracluster reactions upon ionization. The monomer dimer cation potential surfaces explored rationalize observations. cation, observer catalyzes fluorine transfer promotes CF4 formation, ultimately leads ion.