Constraint Satisfaction in Local and Gradient Susceptibility Approximations: Application to a van der Waals Density Functional

John F. Dobson; Bradley P. Dinte

doi:10.1103/PhysRevLett.76.1780

Constraint Satisfaction in Local and Gradient Susceptibility Approximations: Application to a van der Waals Density Functional

John F. Dobson and Bradley P. Dinte

Phys. Rev. Lett. 76, 1780 – Published 11 March 1996

Abstract

We show how charge conservation and reciprocity can be built into local density or gradient approximations for density-density response functions (susceptibilities). We apply these ideas to derive from first principles a variant of the Rapcewicz-Ashcroft formula for the van der Waals interaction. We also discuss how improved formulas may be obtained.