Potential Scaling in Density Functional Theory

Density scaling has a rich history in density functional theory, providing exact conditions for use in the construction of ever more accurate approximations to the unknown exchange-correlation functional. We define a conjugate potential scaling for each density scaling. This provides exact relations on various important density functionals, in particular, relating functionals evaluated on exact densities of different potentials. We illustrate these conditions on the two- and four-electron ion series.