ON THE ACCURACY OF MOLECULAR EXCHANGE-CORRELATION POTENTIALS COMPUTEDFROM ELECTRON-DENSITIES

We examine the accuracy of molecular exchange-correlation potentials c omputed using the method of Zhao, Morrison and Parr, as a function of the basis set and ab initio methodology used to compute the supplied e lectron density. Translational forces, and the potential at nuclei, ar e strongly influenced by core basis functions, while eigenvalues are m ore 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.