The electronic structure of interfaces between aromatic adsorbates and metal oxide surfaces has been investigated using periodic hybrid ab initio Hartree-Fock-density functional theory calculations. Strong interfacial electronic coupling is observed for isonicotinic acid adsorbed on ZnO(10 (1) over bar0) and TiO2(110) surfaces. The results are in good agreement with experiments of ultrafast surface electron transfer processes for TiO2, and current experimental controversies regarding ZnO are clarified theoretically. (C) 2002 Elsevier Science B.V. All rights reserved.