The state of hydroxyl coverage, the presence of admixtures, defects, coadsorbates and also the values of adsorption are shown in electron spectra of the adsorbed luminescence molecules. In the present work we have studied the luminescence spectra of molecules with different electron structures (polyacenes, their N-heteroaromatic analogues, dyes), absorbed on the surface of SiO 2 pure modifications by steady-state and kinetic measurements with UV and selective laser excitation at 300, 77 and 4.2 K. The existence of silica gel and aerosil electron acceptor sites which can form molecular complexes with polyacenes is shown. The number of these sites has been determined. A discussion of their nature is given. The proton—donor capacity of silica hydroxyl groups has been determined at every stage of heat treatment. Adsorption complex geometry on silica surfaces is discussed.