Use of dielectric functions in the theory of dispersion forces

Je Luen Li, Jaehun Chun, Ned S. Wingreen, Roberto Car, Ilhan A. Aksay, Dudley A. Saville

Research output: Contribution to journalArticlepeer-review

44 Scopus citations


The modern theory of dispersion forces uses macroscopic dielectric functions (ω) as a central ingredient. We reexamined the formalism and found that at separation distance <2nm the full dielectric function (ω,k) is needed. The use of (ω,k) results in as much as 30% reduction of the calculated Hamaker constants reported in the current literature. At larger distances, the theory reduces to the traditional method, which uses dielectric functions in the long-wavelength limit. We illustrate the formalism using the example of interaction between two graphite slabs. This example is of importance for intercalation and exfoliation of graphite and for the use of exfoliated graphite in composite materials. The formalism can also be extended to study anisotropic van der Waals interactions.

Original languageEnglish (US)
Article number235412
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number23
StatePublished - Jun 15 2005

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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