A b i n i t i o effective core potentials including relativistic effects. IV. Potential energy curves for the ground and several excited states of Au2

The ground and excited states of Au2 are studied using ab initio averaged relativistic effective core potentials (AREP) and MCSCF–CI procedures. Spin–orbit effects are included in the excited states derived from 2S1/2+2D3/2 and 2S1/2+2D5/2 atomic states using an empirical procedure. The ground state dissociation energy is calculated to be 2.27 eV as compared to the experimental value of 2.31 eV. The calculated energies for the two spectroscopically allowed 0+g to 0+u transitions and other molecular parameters also agree reasonably well with experiment.