Refinements in the characterization of the heterogeneous dynamics of Li ions in lithium metasilicate.
Refinements in the characterization of the heterogeneous dynamics of Li ions in lithium metasilicate.
复制标题
偏硅酸锂中锂离子非均相动力学表征的改进。
DOI：
10.1063/1.2951463
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
K. Ngai
中科院分区：
文献类型：
--
作者：
J. Habasaki;K. Ngai
通过分离局域离子和扩散离子对均方位移（MSD）、非高斯参数α（2）（t）和货车霍韦函数G（s）（r，t）的部分贡献，我们对离子导电的偏硅酸锂Li（2）SiO（3）进行了分子动力学模拟，以更深入地理解异质离子动力学。几种不同的笼尺寸l（c）已被用于定义局域化离子。从所有离子的r（2）（t）中减去定域分量得到快离子的行为，并在所得子系综中发现加速动力学。利用连续跳跃之间的几何相关性解释了MSD的分数幂律。跳跃的等待时间分布也起着决定作用，但不影响其分数幂律时间依赖性的指数。发现部分非高斯参数对于了解长度尺度运动对各种量的贡献有多大是有指导意义的。作为时间的函数，局部离子的部分非高斯参数在t（x2）附近表现出最大值，t（x2）是分数幂律制度的开始时间。最大值的位置稍微取决于l（c）的选择。在最大值之前，非高斯参数的幂律增加归因于连续（长）跳跃的长度尺度的Levy分布。在达到最大值之后，随时间的减小是由于不同长度尺度的运动的大的反向相关。在MSD中具有超线性依赖性的快离子的动力学也在最大值附近的时间开始。还研究了从玻璃态到液态的升温过程中不同区域的特征时间的变化。短时间区和长时间区激活能之间的关系与耦合模型对离子动力学的解释雅阁。
We have performed the molecular dynamics simulations of ionically conducting lithium metasilicate, Li(2)SiO(3), to get a more in depth understanding of the heterogeneous ion dynamics by separating out the partial contributions from localized and diffusive ions to the mean square displacement (MSD) , the non-Gaussian parameter alpha(2)(t), and the van Hove function G(s)(r,t). Several different cage sizes l(c) have been used for the definition of localized ions. Behaviors of fast ions are obtained by the subtraction of the localized component from the r(2)(t) of all ions, and accelerated dynamics is found in the resultant subensemble. The fractional power law of MSD is explained by the geometrical correlation between successive jumps. The waiting time distribution of jumps also plays a role in determining but does not affect the exponent of its fractional power law time dependence. Partial non-Gaussian parameters are found to be instructive to learn how long length-scale motions contribute to various quantities. As a function of time, the partial non-Gaussian parameter for the localized ions exhibits a maximum at around t(x2), the onset time of the fractional power law regime of . The position of the maximum is slightly dependent on the choice of l(c). The power law increases in the non-Gaussian parameter before the maximum are attributed to the Levy distribution of length scales of successive (long) jumps. The decreases with time, after the maximum has been reached, are due to large back correlation of motions of different length scales. The dynamics of fast ions with superlinear dependence in their MSD also start at time around the maximum. Also investigated are the changes of the characteristic times demarcating different regimes of on increasing temperatures from the glassy state to the liquid state. Relation between the activation energies for short time and long time regimes of is in accord with interpretation of ion dynamics by the coupling model.
DOI：
10.1103/physreve.52.2681
发表时间：
1995-09
期刊：
Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics
影响因子：
--
作者：
Habasaki;Okada;Hiwatari
通讯作者：
Habasaki;Okada;Hiwatari
DOI：
--
发表时间：
2005
期刊：
Journal of the Physical Society of Japan 74
影响因子：
--
作者：
小田垣 孝;T.Okubo;T.Odagaki;T.Odagaki;T.Odagaki;T.Odagaki;T.Tao;Y.Kubota;A.Yoshimori
通讯作者：
A.Yoshimori