In my first collaboration with Dr Nicholas Besley, of the University of Nottingham, we investigated the description of near-edge X-ray absorption spectra. In these challenging systems, conventional Coulomb-attenuated functionals such as CAM-B3LYP are not competitive with fixed hybrid functionals that contain large amounts of exact exchange. This is due to the need for short-range exact orbital exchange (functionals such as CAM-B3LYP contain only increased amounts of long-range exact exchange). We developed a series of functionals that contain large amounts of short-range exact exchange, and small amounts of long-range exact exchange, which are able to accurately describe the X-ray absorption spectra. The study also emphasises the difficulty in obtaining functionals that can accurately describe all categories of excitation.

Further information, including details of subsequent work in this area, can be found on the research page. For the abstract, and access to the full text, see below.