Atom substitution effects of [XF6]- in ionic liquids. 2. Theoretical study.
Atom substitution effects of [XF6]- in ionic liquids. 2. Theoretical study.
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DOI：
10.1021/jp8098818
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发表时间：
2009-07
期刊：
影响因子：
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通讯作者：
T. Ishida;K. Nishikawa;H. Shirota
中科院分区：
文献类型：
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作者：
T. Ishida;K. Nishikawa;H. Shirota
在上述光谱研究的基础上，我们进一步通过计算方法研究了[XF 6]-在1-丁基-3-甲基咪唑阳离子（[BMIm]+）离子液体中的原子质量效应对动力学性质的影响.采用从头算方法，对1-丁基-3-甲基咪唑阳离子液体（[BMIm][PF 6]，[BMIm][AsF 6]，[BMIm][SbF 6]）进行了分子动力学模拟.我们计算了态密度（DOS）和速度自相关函数（VACF）的配置文件，极化率时间相关函数（TCF）和克尔谱，中间散射函数，和动力学结构因子。还进行了分解分析，以了解离子种类和运动类型。从这些计算研究中，我们发现阳离子和阴离子的重取向对三种离子液体的Kerr谱的贡献主要是决定性的，而碰撞诱导项和交叉项的贡献在高于50 cm（-1）的频率下并不大，它们与平移运动（包括与平动运动的耦合）有关.结果表明，由于阴离子单元的原子取代效应对离子间相互作用的影响，离子液体的许多性质是可控的。此外，在这项研究中强调，离子液体中的原子质量效应是通过实验和理论方法的互补方法。
Following the preceding spectroscopic study, we further investigate atomic mass effects of [XF6]- in 1-butyl-3-methylimidazolium cation ([BMIm]+) based ionic liquids (ILs) on dynamical natures by a computational approach in this study. We carry out the molecular dynamics simulations for 1-butyl-3-methylimidazolium cation based ILs ([BMIm][PF6], [BMIm][AsF6], and [BMIm][SbF6]) with the development of the force fields of [AsF6]- and [SbF6]- by an ab initio calculation. We have calculated density of state (DOS) and velocity autocorrelation function (VACF) profiles, polarizability time correlation function (TCF) and Kerr spectra, intermediate scattering functions, and dynamical structure factors. The decomposition analysis has been also carried out to understand the ion species and types of motion. From these computational studies, we find that the contribution of the reorientation of cations and anions mainly governs the Kerr spectrum profile in all three ILs, while the contribution of the collision-induced and cross terms, which are related to translational motions including coupling with librational motion, is not large at higher frequencies than 50 cm(-1). It is suggested that, with the atom substitution effects of anion units on interionic interactions, many properties in ILs are controllable. In addition, it is emphasized in this study that atomic mass effects in ILs are accessible through a complementary approach of both experimental and theoretical approaches.