Investigation of the valence electronic structure of n-butane using (e,2e) spectroscopy

Abstract

The first complete (e, 2e) measurements of the valence ionization spectrum (6-56 eV) of n-butane (C4H10) are reported for two relative azimuth angles. Measurements have been carried out using a high-resolution (Delta E = 0.9 eV, Delta p = 0.1 a.u.) spectrometer, using an impact energy of 1200 eV and symmetric non-coplanar kinematics. The results confirm a complete breakdown of the orbital picture of ionization of the innermost C-2s level, as predicted recently by a third-order ADC Green's function calculation. They also point out a strong angular dependence of the relative intensities from which orbital symmetries can easily be traced. (C) 1998 Elsevier Science B.V. All rights reserved.