Broadband terahertz dielectric spectroscopy of alcohols

We have studied the complex dielectric properties of a series of alcohols in 0.5-10 THz frequency range using THz time-domain spectroscopy. The dielectric response observed has contribution from a Debye relaxation process and three damped harmonic oscillators. Combination of experimental observations, all-atom molecular dynamics simulations and ab initio quantum calculations reveals that the complex dielectric spectra of alcohols result from a complex dynamics involving vibrational motions of several atoms across multiple interacting alcohol molecules. The major contribution comes from the fast hydrogen-bond rupture and reformation dynamics, the motion of alkyl chains, and the motions of the H-bonded OH groups. (C) 2017 Elsevier B.V. All rights reserved.