Improved lower bound on the indirect Coulomb energy

Abstract For a Coulomb system of particles of charge e , it has previously been shown that the indirect part of the repulsive Coulomb energy (exchange plus correlation energy) has a lower bound of the form – Ce 2/3 ∫ρ( x ) 4/3 dx , where ρ is the single particle charge density. Here we lower the constant C from the 8.52 previously given to 1.68. We also show that the best possible C is greater than 1.23.