Ortho and Para InterstitialH2in Silicon

Abstract
A Raman scattering study of H2 trapped at the interstitial T site in Si is presented. Both ortho and para nuclear-spin states of H2 and D2 have been observed. It is shown that the Raman signals of H2 and D2 in the J=0 state, where J is the rotational quantum number, disappear preferentially from the spectra during laser excitation or prolonged storage at room temperature in the dark. This surprising behavior is tentatively explained by different diffusion rates of H2 in the J=0 and J=1 states.