Raman scattering study of H 2 in Si

摘要: Isolated interstitial ${\mathrm{H}}_{2}$ and bound to oxygen $(\mathrm{O}\text{--}{\mathrm{H}}_{2})$ in single-crystalline Si are studied by Raman scattering. Two signals at 3199(1) $3193(1)\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ $(T\ensuremath{\rightarrow}0\phantom{\rule{0.3em}{0ex}}\mathrm{K})$ identified as ro-vibrational transitions of HD. Three lines 3727(1), 3733(1), $3740(1)\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ assigned modes hydrogen molecules the $\mathrm{O}\text{--}{\mathrm{H}}_{2}$ complex. By monitoring trapping kinetics it is found that ortho- para-${\mathrm{H}}_{2}$ have similar diffusivities. The temperature dependence ortho-to-para ratio suggests previously reported [E. V. Lavrov J. Weber, Phys. Rev. Lett. 89, 215501 (2002)] absence para species spectra elevated temperatures due thermally activated excitation molecule from $J=0$ $J=2$ rotational state phonon broadening spectral line associated with $J=2$.