Development of new basis sets for quantum chemical calculations

Electronic structure calculations usually express the molecular orbitals as linear combinations of Gaussian basis functions.  However, Gaussians are incapable of accurately modelling the orbital cusps at each of the nuclei and, to compensate for this shortcoming, Gaussian basis sets normally include large numbers of very tight functions.  We have recently analyzed this mathematically and have concluded that it would be beneficial to augment traditional Gaussian basis sets with functions that are explicitly designed to model the orbital cusps.