Repulsión en fuerzas de Van Der Waals

Mainak Sadhukhan and Alexandre Tkatchenko, demostraron que la interacción en un rango largo entre dímeros vdW confinados espacialmente, se vuelve repulsiva cuando se toma en cuenta la interacción completa de Coulomb entre fluctuaciones de carga, les pongo el abstract:

Long-Range Repulsion Between Spatially Confined van der Waals Dimers

It is an undisputed textbook fact that nonretarded van der Waals (vdW) interactions between isotropic dimers are attractive, regardless of the polarizability of the interacting systems or spatial dimensionality. The universality of vdW attraction is attributed to the dipolar coupling between fluctuating electron charge densities. Here, we demonstrate that the long-range interaction between spatially confined vdW dimers becomes repulsive when accounting for the full Coulomb interaction between charge fluctuations. Our analytic results are obtained by using the Coulomb potential as a perturbation over dipole-correlated states for two quantum harmonic oscillators embedded in spaces with reduced dimensionality; however, the long-range repulsion is expected to be a general phenomenon for spatially confined quantum systems. We suggest optical experiments to test our predictions, analyze their relevance in the context of intermolecular interactions in nanoscale environments, and rationalize the recent observation of anomalously strong screening of the lateral vdW interactions between aromatic hydrocarbons adsorbed on metal surfaces.

Miguel Angel Vargas Cruz
2017-07-29 14:16:12 Post #2208