Broadband dielectric response of dichloromethane

Abstract

A systematic study of the dielec. response of dichloromethane over a broad frequency range (8.5 ≤ ν/GHz≤ 1000 ;≤ 4.3 THz at 25°) at temps. from 5° to 35° is reported. The spectra are best described by a superposition of 3 contributions. The dominating loss peak at -70 GHz, fitted by a modified Debye equation accounting for inertial rise, represents the rotational diffusion of mol. dipoles. Addnl., two libration modes contribute, which are described by damped harmonic oscillators of resonance frequencies -0.9 THz and -2.1 THz. While the latter modes reflect the anisotropy of the dichloromethane mol., the diffusive reorientation at long times appears to be rather isotropic.