Computation of three-center overlap integrals over noninteger n Slater type orbitals using ??-ETO

Using complete orthonormal sets of Psi(alpha)-exponential type orbitals (Psi alpha-ETO, alpha = 1.0,-1,-2....), the three-center overlap integrals over noninteger n STO (NISTO) appearing in the evaluation of multicenter-multielectron integrals of central and non-central interaction potentials are calculated. The final results are expressed in terms of one- or two-center overlap integrals between NISTO and integer n STO (ISTO). The formulas obtained are valid for arbitrary noninteger principal quantum numbers, screening parameters, and location of NSTO.