Benchmark values for two‐center Coulomb integrals over slater‐type orbitals

The Löwdin α‐function method, in which displaced orbitals are expanded in an infinite series of spherical harmonics, is implemented for Slater‐type orbitals using a commercial computer algebra program, Mathematica, The program, which is included, generates a C matrix with integer elements that characterizes our approach to multicenter molecular integrals. The general two‐center, two‐electron Coulomb repulsion integral is produced analytically with a finite number of terms. Each Coulomb formula may be evaluated to arbitrary precision, since Mathematica works with integer arithmetic. Hence, cancellation errors can be overcome.