Theoretical and experimental differential cross sections for electron impact excitation of the electronic bands of furfural

We report results from a joint experimental and theoretical investigation into electron scattering from the important industrial species furfural (C₅H₄O₂). Specifically, differential cross sections (DCSs) have been measured and calculated for the electron-impact excitation of the electronic states of C₅H₄O₂. The measurements were carried out at energies in the range 20–40 eV, and for scattered-electron angles between 10° and 90°. The energy resolution of those experiments was typically ∼80 meV. Corresponding Schwinger multichannel method with pseudo-potential calculations, for energies between 6–50 eV and with and without Born-closure, were also performed for a sub-set of the excited electronic-states that were accessed in the measurements. Those calculations were undertaken at the static exchange plus polarisation-level using a minimum orbital basis for single configuration interaction (MOB-SCI) approach. Agreement between the measured and calculated DCSs was qualitatively quite good, although to obtain quantitative accord, the theory would need to incorporate even more channels into the MOB-SCI. The role of multichannel coupling on the computed electronic-state DCSs is also explored in some detail.