A contribution to the understanding of the structure of xenon hexafluoride

Three stationary points of symmetry C_3v, C_2v, and O_h on the potential energy surface of XeF₆ have been located and characterized at the self-consistent field level of theory with a large basis set. At this level of theory, and contrary to results given earlier in the literature, two of these stationary points (C_2v, and O _h) are determined to be transition states, with harmonic vibrational frequencies leading to the third stationary point (C_3v). In addition, second-order Møller-Plesset perturbation theory, configuration interaction, and coupled-cluster energies have been determined at each of these optimized geometries. The C_3v, structure is predicted to lie lowest, followed by the C_2v and then the O_h structure.