Pressure-tuning resonance between the vibron and the libron in CH
Pressure-tuning resonance between the vibron and the libron in CH
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CH 中振动子和力子之间的压力调谐共振
DOI：
10.1103/physrevb.32.4120
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Shimizu
中科院分区：
文献类型：
--
作者：
Shimizu
在金刚石顶压室中测量了分子固体的拉曼光谱，其拉曼光谱最高可达100kbar。对于分子固体，在43和66kbar的交叉压力附近，首次观察到振子和LIBRON之间的压力调谐共振。利用具有相同对称性的两个态之间的共振相互作用理论，分析了观察到的振动模的频率行为以及强度随压力的剧烈变化：在所有的压力下，通过氢化($\mathrm{Cd}}_{2}$${\mathrm{BR}}_{2}$)，未受扰动的LIBRON的频率下移了约21${\mathm{Cm}}{\mathm{ensureath{-}}1}$。这种效应是由于转动惯量的增加而引起的，而转动惯量的增加主要是由于氚原子的运动，也是交叉压强发生变化的主要原因。计算了不同压力下振子与LIBRON的混合系数，并与实验光强比进行了比较，研究了拉曼强度的传递现象。
The Raman spectra of ${\mathrm{CH}}_{2}$${\mathrm{Br}}_{2}$ and ${\mathrm{CD}}_{2}$${\mathrm{Br}}_{2}$ molecular solids have been measured up to 100 kbar in a diamond-anvil cell. The pressure-tuning resonance between the vibron and the libron has been observed for the first time around the crossover pressures of 43 and 66 kbar for ${\mathrm{CH}}_{2}$${\mathrm{Br}}_{2}$ and ${\mathrm{CD}}_{2}$${\mathrm{Br}}_{2}$ molecular solids, respectively. By using the theory of resonance interaction between two states of the same symmetry, we analyzed the frequency behavior of observed vibrational modes as well as the drastic changes in the intensity with pressure: By deuteration (${\mathrm{CD}}_{2}$${\mathrm{Br}}_{2}$) the frequency of the unperturbed libron for ${\mathrm{CH}}_{2}$${\mathrm{Br}}_{2}$ was shifted down by about 21 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ at all pressures. This effect is due to the increase in moment of inertia involving mainly the motion of deuteron atoms, and is the chief cause for the change of the crossover pressure. The coefficients of mixing between the vibron and the libron were calculated at various pressures, and the transfer phenomenon for the Raman intensity was investigated by comparison to the experimental intensity ratio.