Electronic excitation of gas-phase furan molecules by electron impact

Experiments and ab initio calculations of the differential and integral cross sections for the electronic excitation from the ground state ${}^{1}\phantom{\rule{-0.16em}{0ex}}{A}_{1}$ to the ${}^{3}\phantom{\rule{-0.16em}{0ex}}{B}_{2}$ and ${}^{3}\phantom{\rule{-0.16em}{0ex}}{A}_{1}$ states of gas-phase furan molecules by low-energy electron impact were performed. Experimental differential cross sections were measured at incident electron energies between 5 and 15 eV and for scattering angles from 10${}^{\ensuremath{\circ}}$ to 130${}^{\ensuremath{\circ}}$. The calculated cross sections were obtained using the Schwinger multichannel method implemented with pseudopotentials. The influence of channel-coupling and polarization effects is investigated through the comparison between three different models of scattering calculations, each one considering a distinct channel-coupling scheme. The comparison of experimental and calculated cross sections for electronically inelastic electron scattering by C${}_{4}$H${}_{4}$O molecules is found to be mostly reasonable. The existing discrepancies in this combined theoretical and experimental study help to illustrate difficulties in readily establishing reliable electronic excitation cross sections of polyatomic molecules by low-energy electrons.