The photodissociation of CINO2 embedded in argon and water clusters was investigated at 235 nm by detecting the Cl(P-2(3/2)) photofragments with resonance enhanced multiphoton ionization time-of-flight spectroscopy (REMPI-TOF). Under various cluster formation conditions the speed distributions of Cl(P-2(3/2)) were recorded. In contrast to the monomer photolysis only one decay channel was found to be active showing the fragments to be Boltzmann distributed and isotropic. In view of atmospheric chemistry, CINO2 in water clusters is a photolytical source of Cl and NO, radicals with low translational and internal energy. They are thus less favorable for consecutive reactions than the monomer products. (C) 2002 Elsevier Science B.V. All rights reserved.