Diabatic and adiabatic processes in photochemistry

Abstract

Photochemical reactions may be classified as adiabatic or as diabatic whether the chemical change occurs on the same potential energy surface or not. In the adiabatic cases deexcitation occurs either in the reactant (I) or in the product (II) while in the diabatic case it occurs in between them (III). The potential energy surfaces of polyatomic systems are discussed in relation to photochemistry and the possible conditions for the different behaviour of photo-reactions are formulated. Experimental evidence for the appearance of excited products in photoreactions in solution is given. © 1970, Walter de Gruyter. All rights reserved.