Dynamics of xenon, krypton, and methane monolayers in registry with graphite.
Dynamics of xenon, krypton, and methane monolayers in registry with graphite.
复制标题
氙、氪和甲烷单分子层与石墨的动力学。
DOI：
10.1103/physrevb.37.974
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Chui
中科院分区：
文献类型：
--
作者：
Hakim;Glyde;Chui
用自洽声子（SCP）理论研究了氙、氪和甲烷在石墨表面的单分子膜动力学。只有... sqrt.. 3 x.. sqrt.. 3固相。结果表明，石墨单层的声子能量与其浮动单层的声子能量非常相似，而Kr和CH/sub 4/单层与石墨的相互作用对声子色散曲线有显著影响.计算了布里渊区中心声子色散曲线中的差距随温度的变化。在临界温度下，差距自发地变为零，并且发生从锁定相称相到浮动相的转变。这种转变似乎描述了CH/sub 4/ well中与浮动转变相当的转变。浮动过渡的一个简单的模型进行比较，以充分的SCP计算。单声子的动态形状因子，包括三次非谐项，声子寿命也评估为氪和CH/sub 4/。
The self-consistent phonon (SCP) theory is used to study the dynamics of monolayers of xenon, krypton, and methane adsorbed on graphite. Only the ..sqrt..3 x ..sqrt..3 solid phase is considered. It is shown that the phonon energies of the Xe monolayers are very similar to those of their floating counterparts, while the interaction of the Kr and CH/sub 4/ monolayers with the graphite significantly affects the phonon dispersion curves. The gap in the phonon dispersion curves at the center of the Brillouin zone is computed as a function of temperature. At a critical temperature, the gap goes spontaneously to zero and a transition from a locked-in commensurate phase to a floating phase takes place. This transition appears to describe the commensurate to floating transition in CH/sub 4/ well. A simple model of the floating transition is compared to the full SCP calculations. The one-phonon dynamic form factor, including the cubic anharmonic term, and phonon lifetimes are also evaluated for Kr and CH/sub 4/.