  In this study, using the analytical and recurrence relations suggested by the
authors in previous works, the new efficient and reliable program procedure for
the overlap integrals over Slater type orbitals (STOs) is presented. The
proposed procedure guarantees a highly accurate evaluation of the overlap
integrals with arbitrary values of quantum numbers, screening constants and
internuclear distances. It is demonstrated that the computational accuracy of
the proposed procedure is not only dependent on the efficiency of formulas, as
has been discussed previously, but also on a number of other factors including
the used program language package and solvent properties. The numerical results
obtained using the algorithm described in the present work are in a complete
agreement with those obtained using the alternative evaluation procedure. We
notice that the program works without any restrictions and in all range of
integral parameters.
