Ab initio interaction potential of the spin-polarized manganese dimer

Interaction potential of the manganese dimer in its lowest spin-polarized 11 ∑ u + state is investigated ab initio using the coupled cluster method including single, double and non-iterative triple excitations. Special care is taken of the core correlation and the basis set saturation, including extrapolation to the complete basis set limit. The calculations reveal weak dispersion bonding and the following potential parameters Re ≈ 3.69 Å, De ≈ 540 cm−1, D0 ≈ 520 cm−1, ωe ≈ 40 cm−1. Agreement with the experimental and other theoretical data is discussed.