Efficient evaluation of three-center two-electron integrals over Gaussian functions

Abstract

The RI (resolution of the identity) technique achieves significant increases in efficiency for various molecular electronic structure methods. This results from the approximation of four-center two-electron integrals by corresponding three-center integrals. It is shown that the three-center integrals required can be evaluated with a much simpler algorithm than for the general case. This further increases the advantage of RI procedures.