Elastic and excitation processes of electron impact on C3 using the R-matrix method

Abstract

R-matrix calculations are carried out for the scattering of electrons from C3 molecules for an incident electron energy range of 1–10 eV. Elastic differential, integral and momentum transfer cross sections are obtained by summing over rotationally elastic and rotationally inelastic cross sections for rotor states up to J = 4. The excitation cross sections from the ground state of C3, at its equilibrium geometry, to its nine low-lying electronically excited states are also presented. We have included 15 states in the close coupling expansion of the scattering system, where each target state is represented by configuration interaction (CI) wavefunctions. The vertical spectrum of energy levels obtained with CI wavefunctions is in good agreement with other theoretical work. We have detected one shape resonance, two Feshbach resonances and five core-excited shape resonances in the energy range 2–7 eV. The energetics of these resonances and their assignments have been given. We also carried out R-matrix calculations in the static-exchange (SE) and static-exchange plus polarization approximations (SEP) to facilitate the recognition of the nature of the various resonances found. There is no other theoretical or experimental work available for the scattering parameters to compare with our work.