Analytical evaluation of Hylleraas-CI Coulomb and Hybrid two-center integrals over Slater-type orbitals

Two-electron two-center Hybrid and Coulomb repulsion integrals are evaluated with high precision by integrating over the coordinates of one electron and directly over the interelectronic coordinate rij. The use of the Neumann expansion is avoided and therefore, the calculations simplify computations. The resulting expressions depend only on well-known and stable auxiliary integrals and lead to high precision values. Results have been compared with those of other authors. Lists of integrals with different exponents and powers of the interelectronic coordinate are given.