Broadband Dielectric Response of Dichloromethane
Johannes Hunger, Alexander Stoppa, Andreas Thoman, Markus Walther and Richard Buchner,
Chem. Phys. Lett 471 (2009) 85-91. DOI: 10.1016/j.cplett.2009.02.024
A systematic study of the dielectric response of dichloromethane over a broad frequency range
(8.5 <=n/GHz <=1000; <=4.3 THz at 25 °C) at temperatures from
5 °C to 35 °C is reported. The spectra are best described by a superposition of three contributions.
The dominating loss peak at ~70 GHz, fitted by a modified Debye equation accounting for inertial rise,
represents the rotational diffusion of molecular dipoles. Additionally, 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 molecule, the diffusive reorientation
at long times appears to be rather isotropic.