Optical Properties of Nonlocal Dielectrics Independent of Additional Boundary Conditions

Differential equations for the electric fields and polarizations inside a nonlocal dielectric, including a continuous surface potential, are numerically integrated outwards right up to the surface and the reflectivities are calculated for both $s$- and $p$-polarization geometries. We find that for strongly repulsive potentials the choice of boundary conditions additional to those of Maxwell makes no difference to the results.