Faraday cage screening reveals intrinsic aspects of the van der Waals attraction.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30327347.
- Also identified by DOI 10.1073/pnas.1811569115 and PMC identifier 6217410.
- Licence recorded as CC BY-NC-ND.
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Abstract
General properties of the recently observed screening of the van der Waals (vdW) attraction between a silica substrate and silica tip by insertion of graphene are predicted using basic theory and first-principles calculations. Results are then focused on possible practical applications, as well as an understanding of the nature of vdW attraction, considering recent discoveries showing it competing against covalent and ionic bonding. The traditional view of the vdW attraction as arising from pairwise-additive London dispersion forces is considered using Grimme's "D3" method, comparing results to those from Tkatchenko's more general many-body dispersion (MBD) approach, all interpreted in terms of Dobson's general dispersion framework. Encompassing the experimental results, MBD screening of the vdW force between two silica bilayers is shown to scale up to medium separations as 1.25 <i>d</i><sub>e</sub>/<i>d</i>, where <i>d</i> is the bilayer separation and <i>d</i><sub>e</sub> is its equilibrium value, depicting antiscreening approaching and inside <i>d</i><sub>e</sub> Means of unifying this correlation effect with those included in modern density functionals are urgently required.