Growth characteristics of zinc sulfide thin films deposited from dialkylzinc and H2S reactants by the atomic layer deposition technique have been investigated by quantum chemical methods. The steady-state growth of the films was simulated by studying the reaction of the Zn precursor with the hydrogenated sulfur-terminated (111) surface of zincblende ZnS and then by investigating the chemisorption of hydrogen sulfide on the surface formed by the metal exposure. The behavior of the dissociatively chemisorbed Zn precursors on the growth surface is of particular significance for the film deposition process, since the film growth is limited by the Zn deposition step. Hydrogen sulfide exposure results in the replacement of the surface alkyl groups by SH surface species, whose vibrational features are useful in the experimental verification of the developed growth mechanisms.