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Full-Text Articles in Physics
Dielectric Constant In Fluids Of Classical Deformable Molecules, John D. Ramshaw
Dielectric Constant In Fluids Of Classical Deformable Molecules, John D. Ramshaw
Physics Faculty Publications and Presentations
Classical statistical mechanical description of dielectric fluids is further discussed. Dipole moment correlations of polarizable molecules are discussed.
Existence Of The Dielectric Constant In Dipolar Fluid Mixtures, John D. Ramshaw, Norman D. Hamer
Existence Of The Dielectric Constant In Dipolar Fluid Mixtures, John D. Ramshaw, Norman D. Hamer
Physics Faculty Publications and Presentations
The existence of the dielectric constant epsilon is investigated for fluid mixtures of rigid polar molecules. The investigation is performed using the functional-derivative formalism for mixtures, and is closely analogous to that previously carried out for pure dipolar fluids (J. Chem. Phys. 68, 5199 (1978)). Sufficient conditions for the existence of epsilon are obtained in terms of the direct correlation function matrix c/sub alphabeta/(12). It is found that epsilon exists if c/sub alphabeta/(12) depends only on relative positions and orientations, and becomes asymptotic to -theta/sub alphabeta/(12)/kT at long range, where theta/sub alphabeta/(12) is the dipole--dipole potential between a molecule of …
Existence Of The Dielectric Constant In Fluids Of Nonlinear Rigid Polar Molecules, John D. Ramshaw
Existence Of The Dielectric Constant In Fluids Of Nonlinear Rigid Polar Molecules, John D. Ramshaw
Physics Faculty Publications and Presentations
The existence of the dielectric constant epsilon is investigated for fluids composed of nonlinear rigid polar molecules. The investigation is performed using the functional-derivative approach previously employed to establish sufficient conditions for the existence of epsilon in fluids of linear (axially symmetric) molecules. It is shown that these same conditions are sufficient for nonlinear molecules of arbitrary symmetry. An expression for epsilon in terms of the direct correlation function emerges automatically from the development. This expression, which involves the inversion of a 3 x 3 matrix, is a slight generalization of one obtained earlier by Hoye and Stell using an …
Debye–Hückel Theory For Rigid‐Dipole Fluids, John D. Ramshaw
Debye–Hückel Theory For Rigid‐Dipole Fluids, John D. Ramshaw
Physics Faculty Publications and Presentations
The dipolar analog of classical linearized Debye–Hückel theory is formulated for a finite fluid system of arbitrary shape composed of rigid polar molecules. In contrast to the ionic case, the dipolar Debye–Hückel (DDH) theory is nonunique due to an inherent arbitrariness in the choice of a local field E*. This nonuniqueness is expressed in terms of a parameter ϑ related to the ellipticity of the spheroidal cavity used to define E*. The theory then leads to an expression for the direct correlation function c (ϑ) as a function of ϑ. Only the short‐range part of c (ϑ) depends upon ϑ; …
On The Reduction Of Many-Body Dielectric Theories To The Onsager Equation, John D. Ramshaw
On The Reduction Of Many-Body Dielectric Theories To The Onsager Equation, John D. Ramshaw
Physics Faculty Publications and Presentations
An approximate theory for the dielectric constant ℇ of a dense polar fluid was derived by Ramshaw, Schaefer, Waugh, and Deutch (RSWD). In the present article, the RSWD theory is generalized and made rigorous by another method of derivation. The result is a rigorous expression for ℇ which differs from the RSWD expression by the presence of a fluctuation term. Both the rigorous expression and the RSWD expression are then specialized to the Onsager model. It is found that the rigorous expression for ℇ reduces to the Onsager equation, but that the RSWD expression does not because the fluctuation term …