Cost effective calculation of molecular charge distributions and gas phase deprotonation energies using density functional methods

Major advances have been made in density functional theory and linear scaling methods. However, routine application of these methods to larger systems possessing no symmetry still remains difficult. Moreover, no clear standard exists for the use of small basis sets in the calculation of atomic or molecular properties with density functional methods. In this work an evaluation is made of the performance of different density functional methods for small and often used basis sets. Deprotonation energies are calculated for a series of small compounds and compared with high-level quantum chemical calulations. Furthermore, atomic populations calculated with these methods are compared with high-level results. The results show that the use of density functional calculations with smaller basis sets is justified for calculations on larger systems, retaining relatively good accuracies.