Collective dynamics of ionic liquids

Abstract

Collective dynamics of viscous liquids exhibit sound-like modes within the spatial range of intermolecular distances. In this project, we will use Molecular Dynamics (MD) simulations aiming the calculation of acoustic modes of high frequency and wave vector, (k,w). The systems under investigation are the so-called ionic liquids, i.e. room temperature molten salts, and solutions of Li+ in ionic liquids. The MD simulations will be performed at different Li+ concentrations and also as a function of temperature and pressure in order to calculate the high-frequency sound velocity in different thermodynamic states. Polarization effects on the MD simulations will be investigated, and dispersion curves of sound-like modes, w(k), will be compared with experimental data from inelastic X-ray spectroscopy available in the literature. Time correlation functions of mass current of transverse acoustic modes will be used to calculate the generalized viscosity. In the frequency range in which the collective dynamics will be studied by MD simulations (w < 100 cm-1), Raman spectra exhibit intermolecular dynamics that will investigated at low temperatures and high pressures. In this project, we will study the effect of Li+ cation on the Raman spectra of ionic liquids in the vitreous state. (AU)