On the accuracy of molecular exchange-correlation potentials computed from electron densities

We examine the accuracy of molecular exchange-correlation potentials computed using the method of Zhao, Morrison and Parr, as a function of the basis set and ab initio methodology used to compute the supplied electron density. Translational forces, and the potential at nuclei, are strongly influenced by core basis functions, while eigenvalues are more sensitive to diffuse functions. The variation in these quantities with ab initio methodology is rather small. For the case of a Hartree-Fock supplied density, we confirm the validity of the ZMP approach for computing multiplicative exchange potentials for molecular systems. (C) 1997 Elsevier Science B.V.