Metal-Metal Bonding in Cr-Cr and Mo-Mo Dimers: Another Success of Local Spin-Density Theory

Abstract

Self-consistent local-spin-density total-energy calculations for ${\mathrm{Cr}}_2$ and ${\mathrm{Mo}}_2$ yield ${{}_{}{}^1{}_{}{}^{}\Sigma _{\mathrm{g}}^{}{}_{}{}^{}}^{+}$ ground states with dissociation energies and equilibrium bond lengths in excellent agreement with experiment—in marked contrast with the results of a generalized-valence-bond-van der Waals approach, which used 26 512 determinants, and previous local-density efforts. The present results indicate the reliability of local spin-density theory for very inhomogenous systems, when sufficient variational (and symmetry) freedom is included.