We have used photostimulated flash luminescence to study deep electronic states arising when silver ions Ag+ are deposited under high vacuum onto the surface of a ZnS single crystal, followed by creation of the conditions for neutralization of the silver ions. The flux density of the silver ion beam was 107 cm−2·sec−1. We have observed the appearance of two types of deep electronic states with photoionization energies 1.60 eV and 1.80 eV, arising after depositing the silver ions onto the surface of the ZnS single crystal. We have hypothesized that there may be two different preferred sites for adsorption of silver atoms on the zinc sulfide surface. The corresponding photoionization spectra of the adsorbed silver atoms have maxima at 775 nm and 690 nm.