The infra-red spectra of lightly-doped hydrogenated Czochralski-grown material exhibited an absorption that was due to modes of Oi-H2 centers (with a binding energy of 0.26eV), and a mode (ν3HH) at 3618/cm which was due to H2 molecules. Annealing produced reversible changes, in the equilibrium concentrations of Oi-H2 and ν3HH, that revealed a linear anti-correlation. An analysis which was based upon a 2-center statistical model indicated that the number density of available sites for ν3HH centers was 1022 to 1023/cm3. It was proposed that the ν3HH centers were isolated molecules that occupied interstitial lattice sites. The H2 alignment had to be <111> or <110> in order to account for the infra-red activity.

R.E.Pritchard, M.J.Ashwin, J.H.Tucker, R.C.Newman: Physical Review B, 1998, 57[24], R15048-51