Concentration dependence of the charge of atoms adsorbed on single-sheet graphene

Simple schemes for calculating the dependences of the charge $Z_a$ of adatoms on their coverage of a single graphene sheet are developed with allowance for the dipole-dipole repulsion. The proposed schemes are applied to the adsorption of alkali metals and atomic hydrogen. It is established that an increase in the adsorption coverage leads to a decrease in the adatom charge, which concerns both the band and local contributions to this value.