Density fitting for derivatives of Coulomb integrals in ab initio calculations using mixed Gaussian and plane‐wave basis

This article presents an efficient way for evaluation of Coulomb integrals of the type ( k 1 (1) k 2 (1)| g 1 (2) g 2 (2)) and their derivatives with respect to nuclear coordinates by means of density fitting. Symbols k 1 and k 2 stand for plane‐wave functions and g 1 and g 2 for gaussians. The study was undertaken with the objective to accelerate electronic structure and electron scattering calculations in which a mixed Gaussian and plane‐wave basis set is used. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009