Nonlinear dielectric relaxation of polar liquids

Abstract

Molecular dynamics of two water models, SPC/E and TIP3P, at a number of temperatures is used to test the Kivelson-Madden equation connecting single-particle and collective dielectric relaxation times through the Kirkwood factor. The relation is confirmed by simulations and used to estimate the nonlinear effect of the electric field on the dielectric relaxation time. We show that the main effect of the field comes through slowing down of the single-particle rotational dynamics and the relative contribution of the field-induced alteration of the Kirkwood factor is insignificant for water. Theories of nonlinear dielectric relaxation need to mostly account for the effect of the field on rotations of a single dipole in a polar liquid.

Collective Spectroscopy of Solvation Phenomena: Conflicts, Challenges, and Opportunities

“…Computational DRS is based on ”Linear Response Theory” and uses correlation functions of collective dipole moments and electric currents, which is usually sufficient, though very recent advances report on the calculation of the nonlinear contributions as well . In a system containing only neutral molecules, M⃗ tot ( t ) consists only of its rotational part M⃗ D ( t ) = ∑ i μ⃗ i ( t ) which is the sum of the molecular dipole moments.…”