Characterization of Neutral Radicals from a Dissociative Electron Attachment Process
AbstractDespite decades of gas-phase studies on dissociative electron attachment (DEA) to various molecules, as yet there has been no direct detection and characterization of the neutral radical species produced by this process. In this study, we performed stepwise electron spectroscopy to directly measure and characterize the neutrals produced upon zero-electron-energy DEA to the model molecule, carbon tetrachloride (CCl4). We observed the direct yield of the trichloromethyl radical (CCl3·) formed by DEA to CCl4 and measured the appearance energies of all the other neutral species. By combining these experimental findings with high-level quantum chemical calculations, we performed a complete analysis of both the DEA to CCl4 and the subsequent electron-impact ionization of CCl3·. This work paves the way toward a complete experimental characterization of DEA processes, which will lead to a better understanding of the low-energy electron-induced formation of radical species.