  In this work we make some progress on studying four center integrals for the
Coulomb energy for both Hartree Fock (HF) and Density Functional Theory (DFT)
calculations for small molecules. We consider basis wave functions of the form
of an arbitrary radial wave function multiplied by a spherical harmonic and
study four center Coulomb integrals for them. We reformulated these Coulomb
four center integrals in terms of some derivatives of integrals of nearly
factorable functions which then depend on the Bessel transform of the radial
wave functions considered.
