Evaluation of two‐center, two‐ and three‐electron integrals involving correlation factors over Slater‐type orbitals. II. Kinetic and potential energy integrals and examples of numerical results

This article is concerned with the construction of the general algorithm for evaluating two‐center, two‐ and three‐electron integrals occurring in matrix elements of one‐electron operators in the basis of variational correlated functions. This problem has been solved here in prolate spherical coordinates, using the modified and extended form of the Neumann expansion of the interelectronic distance function rkij derived in Part I of this series for k = −1, 0, 1, 2. This work expands the method proposed by one of us in the preceding paper for integrals of the types mentioned above. The results of numerical calculations for different types of the two‐ and three‐electron integrals are presented. The problem of convergence of the proposed procedures used is also discussed.