LOW-ENERGY-ELECTRON SCATTERING CROSS-SECTIONS OF HALOFLUOROCARBONS

The interaction of low-energy electrons with halogenated methanes is important in both their atmospheric and plasma-processing chemistry. In this work, the total electron scattering cross sections of mixed fluorohalomethanes (CF(n)X(4-n)) were measured for incident electrons in the energy range of 0.3-12 eV using electron transmission spectroscopy. Resonances in the scattering cross sections may be interpreted as the capture of low-energy electrons into unoccupied molecular orbitals. To aid in the assignments of the resulting negative ion states, we performed quantum-mechanical calculations of the electron attachment energies. The effect of halogen substitution on the orbitals participating in electron capture are examined.