Department of Chemistry, University of Burgos, 09001 Burgos, Spain.
Department of Chemical Engineering, Qatar University, P.O. Box 2713, Doha, Qatar.
J Chem Phys. 2013 Dec 14;139(22):224502. doi: 10.1063/1.4839635.
The rotational and translational response of cholinium benzoate, cholinium salicylate, piperazinium benzoate, and piperazinium salicylate to static and dynamic external electric fields was studied using non-equilibrium molecular dynamics simulations. The existence of strong intrinsic electric fields in the studied fluids requires intensities larger than 0.25 V Å(-1) to obtain remarkable changes in the fluids' properties, such as rotational motion, dipolar alignment, or ion diffusivities. Very effective dipolar alignment with the applied fields is obtained showing rotational motions in the direction of the applied field, increasing with field intensity and decreasing with field frequency. Translational movement is clearly improved by the applied fields specially for strong fields and low frequencies, which lead to ionic diffusivities increasing up to two orders of magnitude for the stronger fields in comparison with zero field situations, and thus, increasing remarkably fluids' electrical conductivity. The effect of external electric fields on the studied ionic liquids is weaker than in common imidazolium-based ionic liquids.
使用非平衡分子动力学模拟研究了苯甲酸胆碱盐、水杨酸胆碱盐、苯甲酸盐和水杨酸哌嗪盐在静态和动态外电场中的旋转和平移响应。在所研究的流体中存在很强的固有电场，需要大于 0.25 V Å(-1)的强度才能使流体的性质发生明显变化，如旋转运动、偶极取向或离子扩散率。在外电场的作用下，获得了非常有效的偶极取向，表现出沿电场方向的旋转运动，随着场强的增加和场频的降低而增加。外电场明显改善了平移运动，特别是对于强场和低频场，这导致离子扩散率与零场情况相比增加了两个数量级，从而显著提高了流体的电导率。与常见的基于咪唑的离子液体相比，外电场对所研究的离子液体的影响较弱。
