Elastic and inelastic low-energy electron scattering from pyridine

A comprehensive investigation of elastic and inelastic electron scattering from molecular pyridine is reported using ab initio R-matrix method with the static exchange plus polarization and close-coupling approximations for incident energies up to 10 eV. The two well known low-lying 1 2B1 and 1 2A2 shape resonances as well as a 2 2B1 mixed-character resonance compares well with the theoretical and experimental results. We also detect five core-excited resonances (1 2A1, 1 2B2, 3 2B1, 2 2A2 and 4 2B1) which lie above the first electronic excitation threshold. The total elastic cross sections and momentum transfer cross sections agree reasonably with previous reference data. Comparisons of differential elastic cross sections of pyridine with those measured for benzene, pyrazine and pyrimidine show remarkable agreement at scattering angles of above 40{degree sign}, but behave differently for forward scattering below 40{degree sign} below 6 eV, due to the dominant effect of the permanent dipole moment on differential cross section in the low energy region with narrow scattering angles. Inelastic electronic excitation cross sections are presented showing the influence of core-excited resonances below the ionization threshold for the first time.