Molecular dynamics of liquid and supercooled ethyl chloride. A computer simulation

Abstract

The computer simulation method has been used to investigate the molecular dynamics of liquid ethyl chloride at 293 K, under its own vapour pressure, and supercooled at 118 K. The molecular diffusion at both state points is anisotropic, involving strong rotation/translation coupling. In the supercooled condition the orientational autocorrelation function of the dipole unit vector decays almost infinitely slowly, implying the existence of a dielectric loss at very low frequencies (α, or α, β type). The (α, β, γ) theory of dielectric loss, formulated by Evans and Reid, is corroborated by this first computer simulation of the γ process, which appears in the far-infrared.