Unified Treatment of Diatomic Electron Interaction Integrals over Slater-type Atomic Orbitals

General expressions are developed for the evaluation of both Coulomb and hybrid electron repulsion integrals over basis sets of arbitrary Slater-type atomic orbitals. In each case, a single numerical integration over a product of a one-center and a two-center charge distribution function is required for the recovery of the integrals. The one-center charge distribution functions are shared by both integral types. The two-center charge distributions are different for the two cases, but the constants and special functions required are the same. The results lead to an efficient computer-oriented procedure for the resolution of these integrals. The charge distribution functions can be used to obtain two-center overlap, nuclear attraction, kinetic energy, and, somewhat less efficiently, exchange integrals as well.