Wednesday, August 13, 2014

Abstract-Dielectric and Terahertz Spectroscopy of Polarizable and Non-polarizable Water Models: A Comparative Study

J. Phys. Chem. A, Just Accepted Manuscript
DOI: 10.1021/jp507419e
Publication Date (Web): August 13, 2014
Copyright © 2014 American Chemical Society

Using extensive classical molecular dynamics simulations, we compute the dielectric and far infrared spectra of nine popular water models, including polarizable and non-polarizable ones. We analyze the dielectric spectra using a two-relaxation model that allows to extract the characteristic time of both the main dielectric relaxation and, of the fast relaxation. The use of a Cole--Cole functional form permits also to assess quantitatively the absence of deviations from the Debye form of the main dielectric peak. In the THz region of the spectrum we compute the infra-red absorbance caused by molecular libration, which appears to be qualitatively different for three main groups of molecular models. The complexity of the librational band is further investigated by decomposing the spectrum into the contributions of water fractions with different number of hydrogen bonded neighbors.

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