Adsorption of Hydrogen, Alkali Metal, and Halogen Atoms on Graphene: Adatom Charge Calculation

The adsorption of an atom with a single valence s electron (hydrogen, alkali metals) or with a single valence p-vacancy (halogens) on the surface of a graphene monolayer is considered and the adatom charge is calculated. Cases where the adatom-graphene sigma bonds are formed with the participation of p, sp, sp(2), and sp(3) states of carbon atoms are analyzed. It is established that the character of hybridization rather weakly influences the charge transfer. The character of adatom charge variation in the series Li -> Cs and F -> I is analyzed.