Adsorption of Yukawa fluids on a hard wall

We construct a closure theory for the bridge functional based on the third-order Ornstein-Zernike (OZ3) equation. The new closure is tested on the adsorption of the hard-core Yukawa fluid on a planar hard wall and its results are compared with Monte Carlo computer simulation. We show that in the particularly challenging cases of depletive adsorption, the density profiles near the wall obtained from the OZ3 theory improve considerably over conventional liquid-state theories, such as the hypernetted-chain and the Percus-Yevick equations. Some technical details of the implementation of the procedure of re-normalisation of the non-uniform indirect correlation function are also provided.