A perspective on the link between the exchange(-correlation) hole and dispersion forces

In a recent series of papers, Becke and Johnson have proposed an elegant model for London dispersion (van der Waals’) forces in terms of the exchange hole. A perspective on this work is presented here, showing how the exchange-correlation hole is naturally related to “conventional” perturbative approaches to dispersion. The key to establishing this link is the fluctuation-dissipation theorem, which allows the exchange-correlation hole to be …