Nonempirical calculations on diatomic transition metals. II. RHF investigation of lowest closed‐shell states of homonuclear 3d transition‐metal dimers

Potential‐energy curves of the 3 d dimer series Sc 2 through Cu 2 are calculated for the lowest closed‐shell states within the nonempirical RHF formalism using limited basis sets of minimal to near‐double‐zeta–plus‐polarization size. Calculated spectroscopic constants are compared to semiempirical results as well as to experimental estimates. The possibility for closed‐ or open‐shell ground states is discussed for each dimer. For diatomic Sc and Cu a detailed study of basis set effects on calculated molecular constants is carried out.