Impact of anisotropy on the structure and dynamics of ionic liquids: a computational study of 1-butyl-3-methyl-imidazolium trifluoroacetate.
Impact of anisotropy on the structure and dynamics of ionic liquids: a computational study of 1-butyl-3-methyl-imidazolium trifluoroacetate.
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DOI：
10.1063/1.2754690
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发表时间：
2007-07
期刊：
影响因子：
--
通讯作者：
C. Schröder;T. Rudas;G. Neumayr;W. Gansterer;O. Steinhauser
中科院分区：
文献类型：
--
作者：
C. Schröder;T. Rudas;G. Neumayr;W. Gansterer;O. Steinhauser
通过分子动力学方法在 100 ns 的时间内模拟了 1-丁基-3-甲基-咪唑鎓三氟乙酸盐的复杂离子网络。分析了阳离子和阴离子的形状和电荷分布的各向异性对局部（分子）和全局（集体）结构和动力学的影响。方向概率函数 g(r,Omega) 的距离相关 g 系数被发现是解释局部结构的极好方法。因此，各个 g 系数的组合和相互关系阐明了相互的方向。分子水平的动力学特征是质心校正的分子偶极矩mucm的时间相关函数。将一组分子偶极子联合成一个集体旋转偶极矩 MD，研究全局水平的动力学。分解成阳离子和阴离子的子集，可以提取各自的自项以及突出的交叉项。这种分解还可以在介电谱中进行详细的峰值分配。
The complex ionic network of 1-butyl-3-methyl-imidazolium trifluoroacetate was simulated by means of the molecular dynamics methods over a time period of 100 ns. The influence of the anisotropy of the shape and charge distribution of both the cations and the anions on the local (molecular) and global (collective) structure and dynamics is analyzed. The distance-dependent g coefficients of the orientational probability function g(r,Omega) were found to be an excellent way to interpret local structure. Thereby, the combination and interrelation of individual g coefficients elucidate the mutual orientation. Dynamics at the molecular level is characterized by the time correlation function of the center-of-mass corrected molecular dipole moment mucm. Upon uniting the set of molecular dipoles to a single collective rotational dipole moment, MD, dynamics on a global level is studied. Decomposing into subsets of cations and anions respective self terms as well as the prominent cross term can be extracted. This decomposition also enables a detailed peak assignment in dielectric spectra.