Dielectric Relaxation of the Ionic Liquid 1-Ethyl-3-methylimidazolium Ethyl Sulfate: Microwave and Far-IR Properties

Abstract

Dielectric relaxation of the ionic liquid, 1-ethyl-3-methylimidazolium ethyl sulfate (EMIETS), is studied using molecular dynamics (MD) simulations. The collective dynamics of polarization arising from cations and anions are examined. Characteristics of the rovibrational and translational components of polarization dynamics are analyzed to understand their respective roles in the microwave and terahertz regions of dielectric relaxation. The MD results are compared with the experimental low-frequency spectrum of EMIETS, obtained via ultrafast optical Kerr effect (OKE) measurements.

Infrared Spectroscopy of Li+ Solvation in EmimBF4 and in Propylene Carbonate: Ab Initio Molecular Dynamics and Experiment

“…Since J ⃗ is well-defined for individual ions while M ⃗ is not, eq 6 provides a convenient framework to analyze IR contributions from different ionic species, as described below. 34 The electronic contribution to M ⃗ was calculated using two different methods: (i) a Berry phase formulation of the electronic polarization P el 1 57,58 and (ii) localization of electronic charges via maximally localized Wannier functions (MLWFs). 59−61 Calculations of P el 1 with either method were effected via CP2K.…”

“…Compared to prior AIMD studies of IR spectroscopy, , our simulation systems contain a considerably higher number of Li + ions and their MD trajectories are significantly longer in time, allowing for a quantitative comparison with experimental spectra. Combining different analyses, specifically, decomposing the spectral features into auto- and cross-correlations of component currents and calculating solution-phase generalized normal modes , as well as the structure and normal modes of small Li + -containing clusters, we obtain molecular details of IR features of the two electrolytes, including mechanisms for spectral changes engendered by the Li salt. One of the novel aspects of our study is the analysis of correlated motions of constituent ions and molecules and their roles in IR spectra.…”

Wireless‐Powered VOCs Sensor Based on Energy‐Harvesting Metamaterial

“…An analysis of the material properties under the influence of EM waves is important in electromagnetics and related topics, and has been widely studied within the infrared, UV, and visible range. [36,37] In addition, an investigation into a complex dielectric constant is essential in EM wave related research to verify the material properties and EM dissipation energy of materials. However, the material behavior within the microwave frequency range has been relatively less studied, particularly for ionic materials.…”

Molecular Dynamics Simulation Study of the Far-Infrared Spectrum of a Deep Eutectic Solvent

“…For interpretation purposes, it is useful to divide M ( t ) into contributions from the dipole reorientation, D ( t ), and (translational) charge current, J ( t ): M ( t ) = D ( t )+ J ( t ). ,− These are calculated from the configurations of the MD simulation where i runs over molecules, and a over atoms of the molecule i , and CM stands for center of mass. The charge current term is given by where q i is the total charge of a given species: +1 for [Chol] and −1 for Cl.…”

“…We use MD simulations to explore this issue since answering these concerns just from the broad peak seen in the experimental FIR spectra of liquids is not straightforward. The time correlation function of dipole fluctuations must be calculated in order to determine a FIR spectrum using MD simulations. − From both a computational and interpretive standpoint, the calculation in a liquid made up of polyatomic polar molecules and charged species can be divided into contributions resulting from dipole reorientation and translational motions. Schröder and co-workers , used MD simulations to calculate the dipole fluctuations in ILs and the frequency dependence of the dielectric constant.…”