Dynamics is discussed of photodissocn. of chlorine in noble gas matrixes. Dissocn. on repulsive surfaces, harpoon reactions and predissocn. of bound states by curve crossing are discussed using the distribution of electronic states of chlorine in the matrix. It is shown that electronic states and particularly Rydberg states of chlorine as well as ionic and charge-transfer states are significantly modified by the matrix environment. 22 Refs. [on SciFinder (R)]