Dynamics of elemental lithium at megabar pressures
Dynamics of elemental lithium at megabar pressures
复制标题
DOI：
10.1103/physrevb.73.212301
复制
发表时间：
2006-06
影响因子：
3.7
通讯作者：
J. Tse;D. Klug;T. Iitaka
中科院分区：
文献类型：
--
作者：
J. Tse;D. Klug;T. Iitaka
A recent report on the Raman observation of a high-pressure broken-symmetry phase of Li at 120 megabar pressures is examined with first-principles electron structure and phonon calculations. The results show that the observed very high-frequency $\mathrm{Li}\text{\ensuremath{-}}\mathrm{Li}$ vibration, approximately $1800\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$, cannot be reproduced by the ``dimer'' structure proposed earlier or a recently found energetically competitive orthorhombic structure. Model calculations show that such a high Li vibrational frequency could, in principle, be achieved at a $\mathrm{Li}\text{\ensuremath{-}}\mathrm{Li}$ contact less than $1.2\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$ in a linear chain. However, no stable structure was found in the megabar pressure range that satisfies this condition.
A recent report on the Raman observation of a high-pressure broken-symmetry phase of Li at 120 megabar pressures is examined with first-principles electron structure and phonon calculations. The results show that the observed very high-frequency $\mathrm{Li}\text{\ensuremath{-}}\mathrm{Li}$ vibration, approximately $1800\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$, cannot be reproduced by the ``dimer'' structure proposed earlier or a recently found energetically competitive orthorhombic structure. Model calculations show that such a high Li vibrational frequency could, in principle, be achieved at a $\mathrm{Li}\text{\ensuremath{-}}\mathrm{Li}$ contact less than $1.2\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$ in a linear chain. However, no stable structure was found in the megabar pressure range that satisfies this condition.