Vibrational product state dynamics in solution phase bimolecular reactions: Transient infrared study of CN radical reactions

Abstract

Solution phase bimolecular reactions of the CN radical are observed using transient infrared methods. Photolysis of ICN in chloroform produces CN radicals that react after thermalization to form HCN and ClCN as products. In the deuterated solvent, some of the nascent DCN molecules are formed in a vibrationally excited level. This constitutes the first observation of vibrationally excited products subsequent to a bimolecular reaction in solution. Temperature-dependent measurements indicate that the barrier to reaction is low but that solvent friction is important in the reaction. The observed product state energy partitioning and slow reaction rates indicate that the dynamics of reactive barrier crossings are significantly altered upon solvation.