Convergent close-coupling approach to electron-molecule collisions

Over the last few decades it has been the goal of the convergent close-coupling (CCC) method to provide a "complete scattering theory", one capable of accurately describing all processes of interest over the entire range of collision energies for a given scattering system. Whereas previously, different computational methods would be applied to low or high energy collisions, or to different scattering processes such as excitation or ionization, the application of CCC to electron- and positron-atom collisions showed that these can all be studied within a single theoretical framework. On the other hand, even for the simplest diatomic molecules it is still common for different collision processes and energies to be treated using entirely separate techniques. However, with present-day supercomputing resources it is now becoming possible to run large-scale close-coupling calculations for diatomic molecules, from which data for all scattering processes of interest can be extracted. This talk will outline the development of the molecular CCC (MCCC) method and its application to the H₂⁺, H₂, and HeH⁺ molecules. Results will be presented for elastic scattering, rotational, vibrational, and electronic excitation, dissociation, ionization, and Stokes parameters, all calculated in a unified framework over the entire energy range. Recent work on incorporating resonant phenomena into the MCCC method will be discussed, with perspectives on application to dissociative electron attachment.