  We compute the free energy for two rows of localized adsorption sites
embedded in a two dimensional one-component plasma with neutralizing background
density $\rho$. The interaction energy between the adsorption sites is
repulsive. We also compute the average occupation number of the adsorption
sites and compare it to the result for a single row of sites. The exact result
indicates that the discretization does not induce charge asymmetry and no
attractive forces occur.
