Dielectric Properties Of Liquid Water Research Articles

Molecular dynamics simulation of dielectric properties of water

The dielectric properties of liquid water are studied using an empirical potential model treating the monomers as flexible molecules with short-range interactions between oxygens and Coulomb interactions between charges situated on the individual atoms. Satisfactory results for the static dielectric constants at 259, 300, and 350 K are obtained from long simulation runs; these constitute a significant improvement over recent calculations using other potential models. Time correlation functions of dipole moment and single molecule orientation are evaluated. In the supercooled state an enhanced slowing down in the temporal decay of polarization fluctuations occurs, a behavior essentially absent in the single molecule reorientations. Good agreement is found in the self-diffusion coefficient over the entire temperature range.

Note on the dielectric properties of water

The well-known dielectric properties of liquid water and ice have been subjected to extensive analysis in relation to structural parameters. Nevertheless, there remains a considerable degree of uncertainty regarding the applicability of commonly-made assumptions and approximations used in these interpretations and the purpose of this note is to clarify some of these points.

Optical Measurements of Liquid Water in the Vacuum Ultraviolet

Two methods have been used to determine the optical and dielectric properties of liquid water in the vacuum ultraviolet. In the first, the reflectance of water in equilibrium with its vapor at 1°C was measured in the spectral region from 3000 to 1050 Å for three angles of incidence. In the second, water was placed against the plane surface of a transparent semicylinder, which formed one side of a sealed cell, and the reflectance was measured at the water–semicylinder interface. Real and imaginary parts of the complex index of refraction and dielectric constant were deduced from the data and Fresnel's equations. Peaks in the complex dielectric constant occur at 8.3 and 9.6 eV. Though the absorption bands cannot at present be unambiguously assigned, possible mechanisms to explain the ultraviolet structure are presented.