First-principles calculations were performed for various H or muonium charge states. The equilibrium geometry of H+, Ho and H- states, and the relative energies for trigonally symmetrical sites on <111> axes, were determined within 2 configurations of Ga7As7 clusters. Effective core potentials were used for the Ga and As host atoms, and all of the exterior bonds were terminated by H atoms. The present results were compared with available experimental data; especially with regard to recent Mu- results. A very stable H- was predicted which was confined within a tetrahedral interstitial region, with Ga nearest neighbors.

T.R.Adams, M.A.Roberson, R.L.Lichti: Philosophical Magazine B, 1995, 72[2], 183-92