Threshold photoelectron spectroscopy of SF6

The threshold photoelectron spectrum of SF6 has been recorded under good resolution conditions (9-17 meV) over the photon energy range 15.0-28.3 eV using synchrotron radiation and a penetrating-field electron spectrometer, Significant differences have been found between the threshold photoelectron spectrum and the Hell photoelectron spectrum that are ascribed to resonance autoionization processes in the former. The 6t(1u) shape resonance molecular orbital of SF6 appears to play a major role in this regard, This virtual molecular orbital is tentatively located 0.067 eV above the onset of the ionization continuum, The Rydberg series [(2)A(1g)] np(x,y,z) F-1(1u) for n=4-7 of SF6 has been observed by means of resonance autoionization into, most probably, the E (T-2(1u)) ion continuum.