title: Phenomenological model to fit complex permittivity data of water from radio to optical frequencies.
abstract: A general factorized form of the dielectric function together with a fractional model-based parameter estimation method is used to provide an accurate analytical formula for the complex refractive index in water for the frequency range 10(8)-10(16)Hz . The analytical formula is derived using a combination of a microscopic frequency-dependent rational function for adjusting zeros and poles of the dielectric dispersion together with the macroscopic statistical Fermi-Dirac distribution to provide a description of both the real and imaginary parts of the complex permittivity for water. The Fermi-Dirac distribution allows us to model the dramatic reduction in the imaginary part of the permittivity in the visible window of the water spectrum.
authors.affiliation: Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755-8000, USA.
authors.forename: Fridon
authors.initials: F
authors.lastname: Shubitidze
authors.forename: Ulf
authors.initials: U
authors.lastname: Osterberg