Low-energy electron scattering by SF₆

Abstract

In a crossed-beam experiment the authors have studied elastic and vibrationally inelastic scattering of electrons by SF6 over the energy range 50 meV to 1 eV at a fixed angle of 90'. A synchrotron photoionization source was used to form a primary beam of electrons of energy resolution FWHM of about 5 meV. Scattered electrons were analysed with an energy resolution of 11.5 meV allowing us to study the excitation of close lying vibrational modes independently. The authors present excitation functions for v1, v3, 2v1 and v1+v3. Excitation of v3 takes place through a direct dipole mechanism whereas the authors suggest that v1 involves a long-lived negative ion resonance.