Pseudopotential Local-Spin-Density Calculations For Si-2

Pseudopotential local-spin-density calculations of the bond lengths, vibrational energies, and dissociation energies for the $^{3}\ensuremath{\Sigma}_{g}^{\ensuremath{-}}$, $^{3}\ensuremath{\Pi}_{u}$, and two $^{1}\ensuremath{\Sigma}_{g}^{+}$ states of the silicon dimer have been performed. The bond lengths are within 1% and the vibrational frequencies are within 5% of experimental values. The dissociation energy of the ground state is larger than experiment by \ensuremath{\sim}1.25 eV. These results are near the limits of accuracy of the local-spin-density approximation.