Rotation of molecular hydrogen in Si:: Unambiguous identification of ortho-H2 and para-D2 -: art. no. 245503

The 3618.4 and 2642.6 cm(-1) infrared absorption lines of interstitial H-2 and D-2 in silicon have been studied under applied uniaxial stresses. The resulting splittings and their small dependence on isotope establish that H-2 in Si is a nearly free rotor and that these lines arise from vibrational transitions between ro-vibrational states with rotational quantum number J = 1 (T-2 in T-d symmetry) for ortho-H-2 and para-D-2.