A 2-channel model was proposed which accounted for the 2 activation energies which had been observed for H diffusion in crystalline material. A unified model for H and muonium properties (static or thermally activated) was obtained in terms of a stable state at the near bond center site of a metastable state at a tetrahedral site and in terms of energy barrier arguments. The results were obtained via a cluster approach to a Hartree-Fock analysis of the H potential energy surface.

A.A.Bonapasta, A.Lapiccirella, N.Tomassini, M.Capizzi: Europhysics Letters, 1988, 7[2], 145-9