Evaluation of two-electron integrals including the factors r12kexp(−γr212) over Cartesian Gaussian functions Original Research Article

We present a practical scheme for the evaluation of nonstandard two-electron integrals including the factors r12kexp(−γr122) which have been appeared recently, where k⩾−1 is an integer. The method used throughout this paper is based on the highly efficient Head-Gordon and Pople (HGP) approach of evaluation of electron repulsion integrals (ERI). Thus only straightforward modifications of existing codes that employ HGP or HGP-PRISM scheme are necessary to implement our approach.