Gaussian-Transform Method for Molecular Integrals. I. Formulation for Energy Integrals

Abstract

The Gaussian-transform method for the evaluation of multicenter nuclear-attraction and electron-repulsion integrals over one-electron exponential orbitals is described. The basic formulas for 1s orbitals are developed, and machine methods for their extension to higher orbitals are outlined. Computational techniques for the implementation of the Gaussian-transform method are given with emphasis on the requirements for accuracy and speed in the calculations. Possible improvements and extensions of the method are discussed.