Raman and infrared active vibrons and phonons in the solid molecular hydrogen at megabar pressures have been studied by the first-principles band theoretical calculations assuming the hcp lattice of the centers of the molecules. The frequencies of the out-of-phase stretching motion of the two molecules in the unit cell are higher than those of the in-phase stretching motion. Pressure dependence of the frequency of a phonon-like mode, which lies in 1300 cm -1 ∼ 1900 cm -1 at pressures 70 GPa ∼ 200 GPa, is in good agreement with the recent experiments. Our results suggest that the lattice of the solid hydrogen remains hcp beyond the phase transition at 150 GPa.
|ジャーナル||Journal of Low Temperature Physics|
|出版ステータス||Published - 1998 12 1|
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