Vibronic close-coupling calculations of e-H$_2$ scattering

Theoretical studies of electron-molecule collisions are inherently more complicated than electron-atom collisions because of the extra degrees of freedom related to nuclear motion. Close-coupling methods have been shown to be ideal for modeling all scattering processes over wide ranges of incident energies, but the large number of additional reaction channels due to the rovibrational target structure has made close-coupling calculations for molecular scattering systems unfeasible without the use of approximations. Previous calculations performed using vibrational close-coupling techniques have utilized approximate polarisation potentials to account for coupling to excited electronic states, thereby restricting them to studies of electronically-elastic vibrational excitation. Methods which have explicitly included coupling between electronic states, such as molecular convergent close-coupling (MCCC) or $R$-matrix, have relied on the adiabatic-nuclei approximation to decouple the electronic and nuclear motions. The MCCC method has now been extended to explicitly account for the coupling between electronic and vibrational target states using a vibronic close-coupling approach. In this talk we detail the new development and present results for electrons scattering on H$_2$.