Dispersion forces in inhomogeneous planarly layered media: A one-dimensional model for effective polarizabilities

Abstract

Dispersion forces such as van der Waals forces between two microscopic particles, the Casimir-Polder forces between a particle and a macroscopic object or the Casimir force between two dielectric objects are well studied in vacuum. However, in realistic situations the interacting objects are often embedded in an environmental medium. Such a solvent influences the induced dipole interaction. With the framework of macroscopic quantum electrodynamics, these interactions are mediated via A PREPRINT -JUNE 5, 2019Figure 1: Sketch of the considered setups for the spherical problem and the one dimensional analogon: a) Two particles embedded in a medium creating an Onsager's real cavity with inhomogeneous dielectric profile; b) one-dimensional analogon with planarly inhomogeneous profile; c) Two spherical nano-particles embedded in a medium with an inhomogeneous cavity; d) the corresponding one-dimensional problem with two dielectric plates of finite thickness embedded in a medium with inhomogeneous profile.an exchange of virtual photons. Via this method the impact of a homogeneous solvent medium can be expressed as local-field corrections leading to excess polarisabilities which have previously been derived for hard boundary conditions. In order to develop a more realistic description, we investigate on a one-dimensional analog system illustrating the influence of a continuous dielectric profile.

Full-Spectrum High-Resolution Modeling of the Dielectric Function of Water

“…Our calculations assumed a structureless continuum medium. It is possible, however, to incorporate a spatial structure into dispersion calculations …”

“…It is possible, however, to incorporate a spatial structure into dispersion calculations. 74 Lastly, an unavoidable question is how much the water dielectric function will change when very close to the phase transition from the liquid to the solid state, leading to effects for the dielectric function for quasi-liquid water at the triple point not accounted for by considering cold liquid water only.…”

Assessment of the VDW interaction converting DMAPS from the thermal-motion form to the hydrogen-bonded form

“…The cavity type used for PCM calculations was a scaled VDW which places a sphere around each solute atom with the universal force field (UFF) radii 53 scaled by a factor of 1.1. The scaling factor depends on solvent, solute 36 , and the definition of atomic radii 54,55 . Examining the effects of the scaling factors, we found that the results with factor 1.1 fit well to the FIR spectrum at 4 K and can account for temperature-dependent spectral changes.…”

Perspectives on weak interactions in complex materials at different length scales

“…This assumption is questionable due to finite particle size leading to more complex models 283 and concerning the hard wall. 377,378 to point charges screening occurs also for dispersive interactions, where one expects screening by opt ) 2 with the frequency ω opt in the optical range for usual molecular systems. 374,379 Water has ε(ω opt ) ≈ 1.7, such that the screening is much less than for pure Coulomb fields.…”